Fish Health Through Proper Nutrition (revised)[This article was originally posted on February 24, 2006 with the title, Fish Health Through Proper Nutrition; Updated on December 20, 2022]
Author’s NOTE: This is an evolving hobby and, in that spirit, I am bringing this article a current relevance and application. Thank you for your perusal.
I noticed over the years, multiple posts of ornamental marine fish illnesses and conditions which are fundamentally related to a deficient diet, once excellent water quality is achieved. In addition, a proper diet with supplements can help the fish fend off or prevent bacterial infections and some conditions. Bacteria are everywhere. They are ever present in salt water (even tap water has its own nontuberculous mycobacteria5).
The dreaded HLLE (Head and Lateral Line Erosion) may be slowly reversed through proper nutrition and water quality.
35 years ago the pre-packaged foods found at local fish stores (LFSs) were unavailable. Many foods were homemade, according to recipes proposed by Moe (NOT from the Curly, Larry team) and other early authors of marine fish as pets. Feeding Romaine lettuce to herbivore fishes was considered the ‘right’ thing to feed. Now, we know this is wrong3.
What's happening now is like what happened in the 60's and 70's to the human diet. There is now a host of 'fast (fish) foods' that are convenient for the aquarist to feed. Some, like the fast foods of our day, are okay, others are marginally good, some downright little more than buying water.
If reading this post, then it may have referred/referenced. This post was written to focus on a healthy fish diet which includes supplements. Somewhere here is guidance for getting fish back into the healthy mode, with a fully functioning immune system. We want our ornamental marine fishes to not just survive, but to thrive
This post is divided into sections in bold all-caps text. Sub-parts are underlined.
I've heard enough of this: But my fish likes. . . [or] My fish eats. . .[or] My fish only eats. . . to suit me for a lifetime. Who's in charge? Would you let your child eat ice cream and cake for every meal because it's what he/she likes? Prevent marine fish from getting into the wrong habits. Just because the tang eats brine shrimp and mysis doesn't mean it should be eating these foods exclusively. Provide marine fish with what they would be eating in the environment they came from, as often as possible.
My suggestions are all based upon a regime of 21 feedings. This covers fishes that are better off fed three or more times a day, and those that do well twice a day. This regime doesn’t include certain predatory fishes that may only eat once or twice a week. Starting off is:
No matter the types of food fed; supplements are a must – even if the food packaging assures the buyer that it contains all the vitamins and ingredients needed. Our fish are ‘caged.’ They can't seek out the tidbits that provide some trace compounds (e.g., vitamins and fats) they need to round out their optimal health. Fish can't produce all the vitamins they need to live. In fact, they need algae and/or plankton in their die to make their own oil9. So, this must be provided. See the FOOD PREPARATION section for suggestions on how to add supplements to fish foods.
There is one outstanding vitamin suggestion:
Soak food of one feeding in vitamins once a week.
These are some fat supplements:
Maintenance: Fat supplements need to be fed sparingly (once a week for young fish; once every 2+ weeks to older (medium to large) fish) to avoid “fatty liver disease.”
NOTE: Gut loaded brine shrimp with Omega 3 or HUFA type fats feeding may be used during maintenance to replace one fat soaking.
Supplement for sick/ill fishes
A sick or healing (e.g., from an injury, parasite, worm) fish needs more frequent supplements AND an additional supplement.
1. Soak one feeding every day in Vita-Chem .
2. Soak one feeding every day in a fat supplement, e.g., Selcon.
3. Include beta glucan in one feeding every day. Beta glucan is the same beta glucan humans use and can be bought from a health food store. Studies on food fish show that beta glucan has a positive effect on the healing processes  and immunity . Try getting the fish to eat about 20mg of this every day. Beta glucan helps the fish restore its natural immune response to some diseases and conditions . Beta glucan can help heal an injured fish . However, it is not necessary to feed a healthy fish beta glucan if the fish is being fed properly. Combining this supplement in foods can be tricky. Mix it in with its normal food, then bind it in a gelatin form, like using Agar or the product Focus. Having a gram scale that will measure as little as 0.01 grams is useful.
Adding Supplements to Foods
Dry (including pellets and flake foods) and freeze-dried foods are easy when it comes to adding supplements. Soaking in vitamin or fat supplements (see above for supplement suggestions) is straightforward. In a small container or plate, cover the food with the supplement liquid. Let stand 10 minutes. Drain off excess. Feed fish.
Store-bought frozen foods, once thawed and rinsed (see FOOD PREPARATIONS and RINSING sections), may be used too for adding supplements. Put rinsed frozen food/cube into a small container or plate, cover the food with the supplement liquid. Let stand 20 minutes. Drain off excess. Feed fish. This will usually not work with foods in Agar.
When the food is too large for the fish, prepare as described below in the section FOOD PREPARATIONS. Then add the supplement to about half the thickness of the food. Let stand for 20 minutes. Drain off excess liquid. Feed fish. Skip adding supplements when feeding clams on the half-shell, opened oysters, and opened mussels,
BASIC DIETS & FOODS
Determine the kind of foods the fish eats in the wild. Fish can be grouped into one of three basic groups depending upon what they eat. Some fishes ‘straddle’ these basic groups. It’s up to the aquarist to research (not be told by local marine fish store people, friends, or other aquarists) what kinds of food the marine life eats.
One grand exception to following the recommendations below is when seeing the fish eat at the local marine fish store. Whatever kind of fish it is, it is best to be sure the fish is eating in the store, before putting into the quarantine tank at home. Have some of that food on hand and attempt to feed the fish in the QT. But, as soon as possible, get the fish eating the best and natural foods you can offer.
Another worthy consideration is that the following recommendations don’t cover the ‘exotic’ or unusual marine fishes offered by online sellers or sometimes found at the local marine fish store. Also, large carnivores (e.g., Lionfishes) will only eat/be fed once every 7-10 days.
Carnivore fish are fish that eat other marine fish12 and/crustaceans – meat eaters. Fishes like Triggers, Wrasses, Cardinals, etc. are in this group. They don't only eat shrimp tails, etc., they eat the whole organism (except exoskeleton). A natural whole food would be opened clams (prepared as described below or bought frozen, ready to feed) on the half-shell, frozen/freeze-dried krill, frozen/freeze dried whole mysis or mysids, whole (freshwater) mussels, black worms, fish roe (eggs), small ocean amphipods, whole freshwater snails (or just their meat), and frozen/freeze-dried plankton (essential for the fish to synthesize its own fish oils9). Choose the right size or cut/chop/smash into the right size and emphasize feeding whole foods. On the one extreme (and some hobbyists may find this offensive) – QT inexpensive Damsel fishes, medicate and verify they are disease and parasite free and use as feeder fish or euthanize without using chemicals. Some can even be frozen for later feedings. Feeder fish can be injected with supplements (noted above). Shrimp may be QTd with mollies until verified to be disease-free and used as food too, though the preference is to feed marine feeder fish.
Other non-strict carnivores that eat frequently may include young marine fishes of an omnivore nature (e.g., young Tangs). They will dine from the carnivore selections, too.
21 feedings for the carnivores might be something like this:
6 feedings of mysids or mysis (see section below), other pods or amphipods, ocean plankton9 (frozen or freeze-dried of the ‘right size’), Calanus, squid (see preparation recommendations below), and gut loaded brine shrimp (no more than 2 out of 21 of these brine shrimp feedings). One feeding from this group may include decapsulated brine shrimp eggs that don’t hatch if not too small, available from some sources (e.g., Brine Shrimp Direct).
11 feedings of whole ocean organisms (seafood) such as: fresh wild-caught whole ocean shrimp (without shell and smashed if necessary), opened clams and oysters, opened freshwater mussels, scallop (NOTE: Scallops are one of a very few seafoods that contain carbs and is good to feed at least one of these feedings), larger whole ocean plankton9 (smashed to make it the right size), or other marine fish. Read below for preparation of seafoods.
4 feedings Formula 1 (frozen), Prime Reef, products (frozen or freeze-dried) containing (seafood) fish meal, or fish roe (eggs). Fish roe from ocean fish need special preparation. See FOOD PREPARATION section for some suggestions. One feeding for more aggressive or predatory carnivores may be give one or two properly sized live freshwater snail(s).
One feeding in the 21 (once a week) includes one with a vitamin supplement. Every week one feeding with a fat supplement for small fish; medium to larger fish every 2+ weeks.
An omnivore fish eats both flesh/meat and algae. Fish like Anemonefishes (Clownfish) are in this category. Some Clownfish are denied their ‘best diet.’
In general, algae don’t provide a lot of protein, but marine algae are essential for fish to product their own oils9. Omnivore fishes have the 'best of both worlds' in that they can obtain nutrients from meat and get the vitamins/nutrition that algae have to offer. These fish have the greatest diversity of foods they can eat. Over-all no less than 30-35%1 of their diet should be meaty foods. Like the carnivores (above) their ‘meat’ foods need to be whole ocean organisms as much as possible, especially plankton9. Include feedings from the Carnivore section above, and the balance of their diet from the Herbivore section.
One feeding in the 21 (once a week) includes one with a vitamin supplement. Every week one feeding with a fat supplement for small fish; medium to larger fish every 2+ weeks.
Herbivore fish eat seaweed/algae. Fish like Surgeonfish (Tangs), Rabbitfish, etc. fall into this category. They have digestive tracks to extract as many nutrients as possible and to digest the 'tough' algae matter they consume. These fish eat a lot (of algae) and often, and they subsequently usually have a lot of excrement. Wet/fresh seaweed in general isn’t high in protein10 often in the range of 3-4%, so it requires a lot of seaweed/algae to fulfil their dietary protein requirements. These adult fishes cover a lot of reef area in order to eat enough algae. Algae is also important to the fish to synthesize its own fish oils9. They must be provided algae daily – even twice a day. Young fish in this group eat more like the omnivore or even carnivore group and must be fed foods in the above Carnivore section. Older fishes in this group become more and more strict herbivores.
Those who keep these kinds of fish should provide some sandy substrate (even if it is a bare-bottom tank). Many of these species will swallow some sand and very small pieces of gravel. Presumably, this helps in their digestion and grinding up of their vegetable diet. Others theorize that the tang will each some slime algae from the substrate and thus also consume some substrate. For myself, I think of tangs scraping algae from rocks in the wild and it stands to reason, some bits of rock are consumed.
Feeding some meaty foods, especially plankton (another source to synthesize their fish oils9). is needed but no way should they get meat only.
Here's a herbivore mixed 21 feedings example:
3 feedings of mysis or mysids, other ocean pods/amphipods (freeze-dried), ocean plankton, Calanus, or fish roe (eggs – see special preparation ideas below.
7 feedings of Formula 2 (frozen); spirulina loaded foods; kelp loaded foods; spirulina wafers or gelatin based (agar) kelp and/or algae foods; etc.
11 feedings (sometimes twice daily) of seaweed algae (vary sources, and colors -- use red, green, brown, purple and yellow seaweed, homegrown macro algae, or nori (see info below on nori). As the fish gets older/bigger, add more seaweed.
One feeding in the 21 (once a week) includes one with a vitamin supplement. Every week one feeding with a fat supplement for small fish; medium to larger fish every 2+ weeks.
Thus, as an example: When feeding three times a day, each day the fish will get a lot of seaweed/algae or nori (twice/day for older herbivores), a feeding of copepod/krill, and one feeding of a true herbivore food listed above.
BRINE SHRIMP and MYSIS
Brine shrimp (bs) is not found on reefs or in the ocean. Our ornamental marine fishes never ate bs in the wild. These kinds of pods are found in saltwater of higher salinity than that in which the ornamental marine aquarium fish live.
One very nutritious bs food is decapsulated brine shrimp eggs (non-hatching kind (e.g., from Brine Shrimp Direct)). They are small, obviously, but good for very young fish and small-mouthed fishes like wrasses. They can be mixed in with regular foods and homemade foods, too as a fat supplement.
Going down the nutritional chart next are newly hatched brine shrimp, called baby brine shrimp or Artemia nauplii. They still have most if not all the yolk sac. As they grow, they consume their yolk sac very quickly.
Last comes the young adult and adult bs. There is a huge industry built on selling adult brine shrimp to aquarists. Most manufacturers/suppliers will claim how wonderful adult bs are. Local marine fish stores, getting a decent mark-up on bs will recommend bs. It is hard to get to the truth. Adult bs were once called ‘sacs of water.’ They are on the low-end nutritionally6 but most importantly they lack the important nutrients needed by ornamental marine fishes1. Certainly, if the fishes must eat adult bs, then be sure they have been gut loaded with Omega 3, or HUFA, or spirulina. But avoid. In summary: adult bs are BS.
Mysis and Mysids
It seems that, today, “mysis,” means about anything that looks like a small shrimp.. One may also come across the term, “mysid.”
Mysids form a very large classification of creatures in the order Mysida. There are a surprisingly wide variety -- there are over 1,000 species in this classification! They range in size from 5 to 30mm (0.2 to 1.2 inches). They look a lot like shrimp but aren’t. One of the more famous mysids is, Americamysis bahia. These come from saltwater and have been called: opossum shrimp (as do many other mysids), mysid shrimp, and mysis shrimp. See how confusing the naming can be?
Mysis is a genus of the family Mysidae. So mysis is technically a group within the large classification of mysids. There are 15 species of mysis ranging from 1 to 3 centimeters (0.4 to 1.2 inches). Obviously, only the small ones are of interest to our small and medium sized ornamental marine fishes.
Both mysis and mysids can be found in freshwater and seawater. The ones best for ornamental marine fishes are the ones found in seawater. Second choice would be those found in brackish waters. Is it bad to feed marine fish freshwater mysids? No – assuming the fish eats additional seafood offered in most meals.
Whichever classification is chosen (mysids or mysis) there are two goals: The right size and that they are seafood (come from the ocean). Oversized foods can be chopped and/or smashed.
Today, we have smart phones and watches and the Internet. If the food container gives the name of the organism(s) and nothing more, then look it up to learn more.
READ THE INGREDIENTS/CONTENTS LIST WHEN BUYING PREPARED FOODS!
I can’t emphasize the importance of reading labels. Whether bought online or at the LFS, read/review the ingredients and contents list. There is a list below of possible prepared foods to consider if you don’t wish to go through the effort of doing the FOOD PREPARATIONs.
If in doubt about the meaning or origin of any ingredient, check it out on a smart phone or smart watch. This can be done while in your local fish store or on the Internet.
Wheat, wheat gluten, wheat germ, wheat starch, flour, soy, etc ingredients.
Wheat products are foreign foods to the ornamental marine fish. The label on foods containing wheat products will boast a % protein BUT, that includes the wheat and soy protein. Wheat is often used as a binding agent in pellet and flake foods. There are agar-based foods that do not contain wheat. It isn’t a ‘crime’ to feed wheat containing pellets or flakes to marine fish but be sure it is a rare feeding. Avoid foods that list 2 or more wheat products in their first 5 ingredients. I have fed a pellet or flake feeding once or twice a week when I was late for work. They aren’t bad per se just not seafood. I liken it to eating a well balance meal of fresh meats, fruits and vegetables to a meal of Twinkies and donuts. Are Twinkies and donuts bad? Maybe not. But they aren’t a staple diet. Want an easy way to remember this?
Food flakes, pellets, wheat, soy, etc. are not found in the ocean. Go for natural ingredients.
Examples of pellet ingredients from different makers are on this and the next page.
One of the least preferred marine fish pellet foods that I have come across.
Reading this Ingredients List
Fish Meal is first. A good ingredient. Learn what Fish Meal could contain.
Next two ingredients are wheat products. Not preferred.
Fish Oil is next ingredient. Learn what Fish Oil could contain. Oil from what kind of fish(es)? The oil from freshwater fishes and marine fishes has different contents.
Animal Protein. What animal? Sounds like it is a land animal. Not preferred.
Soy Lecithin – Land product. Not preferred.
Spirulina is next and a very good ingredient. It is 7th on the list. An essential ingredient9.
Paracoccus – a denitrifying Gram-Negative bacteria as a pigment?
Bentonite = Clay. How much clay do you believe is needed in your fish’s diet?
Dicalcium Phosphate – Does your aquarium need more phosphates?
L-ascorbyl-2-polyphospahte (Vitamin C) - Is this the right Vitamin C for ornamental marine fishes? Yes. It is a stabilized Vitamin C. Good ingredient – 12th on the list.
Not worth reading any more. I would have stopped reading the ingredients list of this pellet when I got to Animal Protein.
The above pellet ‘food’ (and I use the term loosely) is something to pass up. There are better pellet foods to choose from. Not Preferred.
On the following page is a group of pellet food ingredient labels and levels of preference.
I’m not a fan of flake foods. Like most flakes they have been heated. They don’t retain oils and any oils that may be there become rancid quickly. However, having found Brine Shrimp Direct marine fish flake foods, I believe they have the optimal formula and optimal in-house small batch processing. Try their flakes, if you use flakes.
To a small degree the health of marine fish depends upon obtaining some nutrients directly from the water they swim in.1 They need and use 13 trace elements known as ‘micro facilitators’ found in their water environment. Where we fail them sometimes is keeping them long term in water that has been depleted of these elements or contains these elements in concentrations too low for them.
The use of synthetic sea salts and saltwater mixes isn't the problem. The problem is sometimes aquarists 'over clean' the water. The worst offender is activated carbon. Activated carbon removes organics the first time it is put into our system. After some time, carbon removes trace elements11 (and sometimes adds phosphates depending on the type of carbon). It's the removal of trace elements that needs monitoring. I've had long-term success with using carbon or carbon-like substances every other week and each time no more than 5-7 days, then removing or replacing it from the system to prevent the abnormal depletion of trace elements. However, there may be a need or desire to use carbon more frequently. Be diligent with water changes to replenish the trace elements.
Adding small quantities of trace elements for fish is not necessary with the better types of salts available AND proper water changes. In addition, for this reason (if not for the many other reasons) make sure to perform regular water changes.
Now, for more pellet list of ingredients. . .
The above recommendations cover a wide variety of foods – frozen, freeze-dried, gelatins, and air-/sun-dried. You may choose to buy prepared foods and add supplements. You may wish to try some preparations of your own or do a mix of the suggested preparations listed below. If only using store-bought foods, just skim this section.
Preparation of seafoods and foods for homemade fish foods
NOTE: When feeding ocean sourced foods remember that diseases may be transmitted.7 See the RINSING section below for final handling of these foods.
Most often, these fresh seafoods are acquired from the grocery store or seafood store and/or a local marine fish store. Seafood shopping guidelines are found in Reference 77.
Clean fresh squid in tap water. Remove guts, ink, the cartilage, and beak. Keep the eyes, tentacles and body. Pre-smash if necessary. Chop if necessary. Or keep whole for homemade fish food. I recommend not including guts since the gut content may contain bacteria foreign to the aquarium. Other hobbyists choose to include guts.
Smash open medium sized freshwater snails and use the meats. Since they are freshwater, there is no concern about diseases or parasites.
Rinse off (tap water) fresh caught (hopefully wild-caught) whole shrimp (with heads on). Remove all exoskeleton/shell and legs/feet. De-vein. Pre-smash or chop if necessary. Or keep whole for homemade fish food. For the same reason I don’t recommend using squid guts, I recommend removing the ‘vein’ of the shrimp. Other hobbyists include the vein.
Live ocean clams people eat (e.g., Mercenaria mercenaria, Arctica islandica, or Spisula solidissima) still in the shell. Clean outside with vegetable brush in tap water. Don’t ‘cook’ the clam, but stubborn clams that won’t open may be warmed (125F) in an oven. Check frequently (every 5 mins). They will often open enough to get a knife in. Rinse inside of clam per Rinsing subsection, below. NOTE: Do not feed clams to fish unless that clam has been frozen as recommended below. Thaw clam. (I have also added the frozen, opened clam to my large aquarium. It thaws fast enough). If thawing before putting in the aquarium is preferred, give a final rinse with RODI water.
Fish roe (eggs) come in different sizes, depending upon the fish source. Almost all ornamental marine fish will eat fish roe. Tiny roe comes from smelt, larger ones from salmon. Filter, then rinse as described in the RINSING section below. If the fish roe is purchased frozen as a fish food, filter and rinse as recommended in the RINSING section below.
Raw crab meat. Remove shell and cartilage. Process as in RINSING 2.
In the case of freshwater mussels, clean outside with a vegetable brush, open, and rinse in RODI water. They can be fed as is, or frozen for later use. Rinsing the inside is important since these clams usually contain their favorite foods – detritus.
Whole foods (e.g., small feeder fish) fed to predatory carnivores can be ‘loaded’ with a supplement. With a syringe, squirt 0.5ml of supplement into the mouth of the fish. Some will spill out, but your pet fish should eat it quickly.
Do you see/notice any commonality in the above foods? What do the above food suggestions have in common? Answer follows in the Homemade Foods subsection.
Store all dry foods and supplements in the refrigerator (even pellets and flakes). Buy the freshest foods possible and don't buy more than your fish will eat in two months or so. If bulk pricing is too good to pass up, then combine a food order with fellow aquarists to get the discount, but do not get the bulk, long range volume unless you have a very large group of fish. Some dry foods may be frozen up to 8 months before thawing and using. Still, the fresher the better.
Frozen foods should be kept in the freezer then thawed and rinsed before feeding (see RINSING section). Store-bought frozen fish foods need to be kept at -20°C (-4°F) for 7+ days7. Most home freezers are set to 0°F. For fish foods, the home freezer is best set to -4°F or less, if adjustable. How was the fish food processed, then initially frozen, then kept frozen until it got to the local marine fish store? It’s unknown to me. Thus I keep it frozen at -20°C (-4°F) for 7+ days before first use.
If the frozen food has been through a sterilizing process (e.g., gamma radiation), then storing it in a conventional freezer at 0°C (32°F) is suitable.
BUYING PREPARED FOODS
Included in this section are foods bought at the local marine fish store, or online. The local marine fish store usually carries many frozen, ‘in between,’ and freeze-dried food choices, but the buyer needs to be aware that frozen foods, though usually safe can present a concern.7 (See subsection Frozen Foods). The best alternative is usually a freeze-dried choice.
Freeze-dried ocean foods avoid diseases. Another advantage of freeze-dried foods is that they will absorb the recommended (see above) vitamin and fat supplements. A disadvantage is that they often float. I have put the food in saltwater and ‘crushed’ them with a spoon to squeeze the air out of them. A more elaborate approach is found in this video: Getting Air Out of Freeze-Dried Food.
I like to use freeze-dried pods like:
Calanus finmarchicus - from Amazon or Brine Shrimp Direct
Small-mouth feeders and young fishes will probably eat Amzey’s Artemia Nauplii
From Amazon and other sources.
Freeze-dried blackworms (Lumbriculus variegatus) [not ocean based but I make an exception for a rare feeding]
Freeze-dried Ocean Plankton
Hikari Bio-Pure Freeze Ocean Plankton for Pets
From Brine Shrimp Direct:
Freeze-dried krill. May need some chopping up.
Decapsulated brine shrimp eggs (non-hatching kind) – Great for small-mouthed or young fishes like cleaner wrasses (also available from Amzey)
Freeze-Dried Daphnia (being freshwater, best not to feed too often).
Chewy.com carries both the following:
Omega One freeze-dried Pacific Plankton
San Francisco Brand freeze-dried (ocean) plankton.
You’ll find other sources for these products. Your local marine fish store may carry one or more. Also, something not on the list is freeze-dried or frozen spirulina or fat gut-loaded frozen brine shrimp. I'm not a fan of brine shrimp in general, but the gut loaded one can also be fed, sparingly, like blackworms (Lumbriculus variegatus).
Freeze-dried bloodworms (Lumbriculus variegatus) are found in local fish stores and online. Often wrongly referred to as Tubifex Worms. The name Bloodworm is ambiguous, but they are for the most part, aquatic. Some bloodworms are freshwater bloodworms; some are saltwater bloodworms. The marine hobby primarily uses Lumbriculus variegatus.
Freeze-dried Tubifex Worms are available from multiple makers.
In-between types of food (not freeze-dried nor frozen)
Nutramar Marine Complete food shots from eBay or Saltwaterfish.com, and others.
Easy Masstick Fish Food Tabs from Bulk Reef Supply and others.
Herbivore packaged foods
Be aware of how the seaweed dried. Don’t use/buy seaweeds that have been heated or ‘roasted.’
Marine Seaweed/Algae from any of these sources:
Amzey sheets (various colors) (website);
Omega One & Seaweed Salad (Chewy.com and others);
Ocean Nutrition’s Marine Algae sheets (various colors) (Amazon);
Green Seaweed sheets from China (Amazon);
Nori (don’t use the kind that has been roasted dry or with additives).
So, when I use frozen foods, I rinse as explained in the RINSING section.
I know, I know. . .Many aquarists might think my methods an overkill. But I find it best to be conservative when it comes to feeding my ornamental marine fishes. Choose your level of care and strategy. This is the way I do it.
Carnivore/Omnivore frozen food examples:
Frozen clams on the half-shell
PE Frozen Mysis (diluviana) Shrimp
PE Frozen Calanus (to aid in marine fish coloration)
Hikari Mega-Marine Angel food (frozen)
Ocean nutrition angel formula
R.O.E. Real Oceanic Eggs by Reef Nutrition
LRS Herbivore diet
Amzey brine shrimp Nauplii (good for small-mouth feeders and young fishes)
Keep some aquarium water taken out for the water exchange (assuming the tank water quality is excellent). Rotate this ‘stock’ (i.e., dump saved water and replace with ‘new water’ taken out for a water exchange).
There are two kinds of rinsing procedures.
1. The rinsing of pre-packaged, store bought frozen marine fish foods, and 2. The rinsing of fresh seafoods bought from grocery stores or a fish market and subsequent freezing. You may think this ‘overkill.’ But this is how I do it.
Rinse all frozen foods (e.g., cubes, flats, bars) before feeding to reduce aquarium pollution like this: Place frozen food inside of a baby brine shrimp net. Let thaw. (See photos). Rinse with used saltwater. Then take used salt water and rinse the thawed food again. Throw out the water that has passed through the net. (See photo on right). Add a supplement (per above recommendations) when appropriate. Feed fish. If the frozen food is in large pieces (e.g., shrimp, krill) use a fine fish net or rice strainer for rinsing. The amount of water used to rinse should vary with the amount of frozen food that is to be rinsed. Don’t be stingy. Use no less than ½ cup for even the smallest amount, or one cube. Use more, a lot more, if there is a large quantity to rinse or rinse water is heavily polluted. A large ‘batch’ of frozen foods may be rinsed like this then refrozen, but the re-freezing may create additional ‘particulates.’
Perform multiple rinses until the pieces of food are large/small enough for the fish to eat.
2. The rinsing and preparation of fresh seafoods. These foods may pose an additional health concern for ornamental marine fishes7. Here, I perform two steps: rinsing and freezing. First step: The fresh seafood, after prepared per Preparation of seafoods and foods for homemade fish foods subsection, is given tap water rinses, then soaked in RODI for 2 hours (refrigerated if you like). The seafood is strained of this RODI, then soaked again in fresh RODI for 2 hours. The seafood is strained of this RODI.
The second step: freeze this rinsed seafood at -20°C (-4°F) for 7+ days. This freezing has been advised for the destruction of human parasites7 which I believe includes marine fish parasites and diseases. Most home freezers are set at -17.8°C or 0°F. But many can be set lower. Check your freezer.
Feeding live foods is a huge benefit for marine fish. This is the ‘ultimate’ delight and drives fish’s health to their maximum level. The worms listed are freshwater or land worms, but still, being a whole and living food supersedes the concern of not being seafood.
Search eBay and the Internet to buy these worms as starter cultures – many can be homegrown. Look for: Micro Worms (very small as the name implies), Grindle Worms (Enchytraeus buchholzi), and White Worms (like Enchytraeus albidus).
The genus Enchytraeus includes about 40 species of annelid worms. The term “white worm” is often used for all the species in general, but specifically it is E. albidus which is named after the white worm commonly raised and fed to tropical fishes.
If you choose to grow your own White Worms (like I do), you’ll be advised through the Internet on how culture them. Some live best at different temperatures. I think the best food to feed the worms is marine fish food. This is something useful for outdated dry marine foods (e.g., flake, pellet) or moist pellet food, like (my personal favorite) Nutramar Marine Complete food shots. Doesn’t it make better sense to feed these worms with fish food? The more nutritious the feed, the more nutritious the worm.
Pick the size of the worm(s) suitable for your fish. Keep in mind that worms that are too long can be cut smaller, although many in this genus are small. When added to saltwater, they sink and if not eaten, will eventually die. Remove uneaten worms to eliminate pollution.
Blackworms and Other Worms
Live Blackworms (a.k.a. California Blackworms) (Lumbriculus variegatus) can be bought online. Most availability seems to be from biological supply companies, and just a few sources of reptile companies. Lumbriculus variegatus are primarily for medium to large marine carnivores/omnivores, although most fish will eat, and benefit from, them. Even though they are freshwater, they are still very nutritious, and they are after all, alive. Since they are freshwater, diseases aren’t an issue. Blackworms may be homegrown but with some effort.
Tubifex Worms are a large group of worm species, most of which are not preferred as live marine fish food. They grow in mud, sludge, and sewage. The Tubifex tubifex worm is the most common live Tubifex Worm fed to marine fishes. They are a challenge to cultivate at home, so the Blackworm may be the best choice if culturing is the objective. They are now available from professional worm farmers and biological suppliers, but if the Tubifex tubifex worm is harvested from the wild it may be best to keep the worms a while to void the contents of their digestive track.
All these worms come from freshwater, so they will sink and die if left uneaten, in the home marine aquarium. Remove uneaten worms to eliminate pollution.
If your fish is an aggressive carnivore of medium to large size or perhaps one of the predatory fishes (e.g., puffers, triggerfishes), it may like to eat live freshwater snails. Get some freshwater snails and drop them into the tank.
Another in this group of foods for aggressive carnivores are live ghost shrimp, also known as “glass shrimp.”
I have fed live mosquito larvae to my marine fishes too.
Pod eaters will greatly benefit from live copepods and fishes in general will eat live amphipods (of the right size). Be cautious since some come from the ocean and others come from freshwater. If the provider of live ocean pods is dependable, their stock should be disease-free. Buyer beware.
I’ve never fed live Daphnia to marine fishes but read where they can. They contain Vitamins A and D and their movement should ‘awaken’ the hunting practice of small (or young) marine carnivores and omnivores. They won’t live in saltwater.
Live seaweeds/macro algae for herbivores (caution about source or, grow your own)
Marbled Crayfish or Marmorkrebs (Procambarus virginalis) (of appropriate size) have been fed to aggressive carnivores.
Don’t even think of feeding live adult brine shrimp. They are low in nutrition. They do have a use, though. If a fish isn’t eating, something living, swimming around will attract the fish’s attention and get It eating. But wean it off this live food as fast as possible, once the fish starts eating
HOMEMADE FISH FOOD
First, prepare the fresh seafoods as recommended above in Preparation of seafoods and foods for homemade fish food. Follow RINSING recommendations. Buy Agar Agar or Agar (unflavored with no additives). This is the basis for Jell-O. About 3 ounces will be sufficient for an average sized (4 cup) batch. Next step is to make the “Food Blend.”
I made a (poor) video. But before you watch the video you need to know that the quantities in the video are not good enough. Trying to be conservative, too little was made. Too much Food Blend is lost in the transfers – from the blender and then from the large bowl to the measuring cup. So, use the quantities given in this post and view the video to get a general understanding of the process. Click on this link to view my Making Homemade Saltwater Fish Food video.
The goal is to prepare the amount (volume) of Food Blend a little more than the volume of Agar being prepared.
Sample recipe for a medium sized batch of food
1 small squid (remove ink sac, beak, guts, and cartilage but keep the body, eyes, and tentacles)
3 medium or 2 large or 5 small clam meats
2 or 3 medium sized freshwater snail meat (optional)
3 medium scallops or 6 - 8 baby scallops
3 medium shrimp or 4 - 6 small shrimps (heads on, all exoskeleton removed & de-veined)
½ ounce freeze-dried Calanus finmarchicus pods
2 oz powdered ocean plankton
30ml Selcon (cold)
30ml approximately, Garlic Juice (I make my own, fresh on the day of use)
¼ cup (60ml) Vita-Chem (cold)
[other semi-liquids may be included, such as filtered cold ocean roe (fish eggs)]
Have on hand 4+ oz. freeze-dried ocean plankton to add at the end to thicken Food Blend
1 ounce powdered Spirulina (to add to the liquified Food Blend in oversized bowl)
3 Tablespoons + 1 teaspoon of Agar Agar or Agar (3 level Tablespoons + 1 level teaspoon)
2 cups RODI for Agar preparation
Use a custom recipe of your own. Be creative but follow the guidelines. All fresh seafood was prepared as outlined Preparation of seafoods and foods for homemade fish food then further processed in RINSING. Scale down (1/2) or scale up (2X) this recipe for your needs.
If you scale down, be sure you are using a blender that will liquify small quantities. All equipment used (blender, pot for Agar, measuring cups & spoons, stirring spoon, thermometer, oversized bowl, small food chopper, etc.) were pre-rinsed in tap water then rinsed several times in RODI water before use.
I know, I know. . .Many aquarists might think my methods an overkill. But I find it best to be conservative when it comes to feeding my ornamental marine fishes. Decide for yourself.
Make room in the/your refrigerator for the final plate, dish, or cookie sheet to sit level.
Make the “Food Blend”
In a blender put in water (usually best to use less, since more is easily added when needed) and other liquids (e.g., Vita-Chem8, Selcon, ocean roe, Garlic Juice). Begin with a total of 1 ¾ cup of liquid. The way I do it is adding all liquids (excluding water) to a 2-cup graduated measuring cup. Top off the liquid to the 1 ¾ mark on the cup with RODI water or, I like to top off with rinsed, cold ocean roe and RODI. Put this liquid into the blender.
Add semi-frozen seafoods starting with the softest then ending with the firmer (e.g., first squid, then scallops, then clam meat, then shrimp, then Calanus and finally the powdered ocean plankton). Liquifying this mix may generate heat. To avoid overheating/cooking the Food Blend, I use partially frozen or cold ingredients and cold water (or cold roe) to top off the 1 ¾ cup. I have added crushed RODI ice to the blender to thin the mix, too. Now blend to liquify but not to cook or heat up. If the liquified food is thick (which it usually won’t be at this point), add more cold water or crushed ice to make it a bit thin (on purpose). If too thin. add some freeze-dried ocean plankton to make it about the right thickness. Blend again to liquify. The thickness should be like a thick milk shake.
Pour blended liquid into an oversized bowl.
Add Spirulina powder to the bowl of blended liquid. [I always include spirulina powder (an alga) and ocean plankton since our ornamental marine fishes use these to make their oil10]. This now is the Food Blend. If you believe the mix is too thin, add some thickening ingredients. Some thickening ingredients include but are not limited to: decapsulated brine shrimp eggs (unable to hatch), additional powdered ocean plankton, and powdered pods/mysis. I let this mix sit for an hour. [Now is a good time to start cleaning up. If you let equipment dry out, it is much more difficult to clean.]
Remember: marine fish are on a strict raw seafood diet! Some other choices to consider for the Food Blend, include those given in the Preparation of seafoods and foods for homemade fish food.
Did you by any chance notice the commonality of the fresh seafoods listed in the Preparation of seafoods and foods for homemade fish food subsection? Perhaps not that easy to see. But those foods are found either in the plankton zone (where most of the wild-caught ornamental marine fishes first began eating) or the bottom of the ocean. Ornamental marine fishes don’t eat smelt, salmon, cod, or schooling ocean fishes, thus I don’t include them in homemade fish food recipes. Use foods found at the top or bottom of the ocean – their natural foods – for homemade food. Add more shrimp if a higher protein food is desired.
Do not include pellets, wafers, flakes, adult brine shrimp, or any (other than Garlic Juice or freshwater snail meat) land product.
As noted above, this mix should sit (about an hour) so all dry foods absorb as much liquid as needed and allow the larger bubbles to surface. Also as advised above: Do kitchen clean up. Waiting just makes cleaning up harder. After the resting time, the Food Blend should roll off the large spoon like cake batter, or a thick pancake batter. Best to be too thick than runny (easier to add water than remove it). Make sure the Food Blend is at room temperature before proceeding.
Measure out 2 cups (in the case of this recipe) of the Food Blend for the equal amount of Agar (2 cups in the case of this recipe) to prepare as given below. Hold the Food Blend off to the side. Now. . .
Prepare the Agar
Add the Agar to cold or room temperature RODI in a pot at least 2.5 times the quantity being prepared (2 qt pot for this recipe). It is important to use cold or room temperature RODI. (If you attempt to use hot water, it will make a mess). The quantity of Agar powder used is about 2.1 times the ‘normal’ quantity recommended on the Agar package. [The Food Blend, when added to the Agar, will dilute the Agar to a high-normal final concentration. The final concentration of Agar in the final mix (Food Blend + Agar) is about at 3%.]
Slowly heat the Agar/water mix. This is so the Agar properly rehydrates. Stir occasionally until the Agar begins to melt/dissolve (usually between 80C to 95C (175-203F)). It’s okay if the hot Agar isn’t clear. Keep slowly heating, stirring occasionally until the first signs of boiling. Don’t be fooled by bubbles coming from the heat source, the target here is to have the entire mix gently boil. Now start the timer. Gently boil for about 3-4 minutes while constantly stirring. Do not over-boil – Do not underboil. Turn off the heat. Insert thermometer into the melted Agar. Let the pot of Agar slowly cool with very frequent stirring. Clumps tend to form on the bottom of the pot, so stir and ‘scrape’ the clumps off the bottom using the plastic stirring spoon.
The objective is to allow the agar mixture to cool to a temperature so when the Food Blend is added, the food doesn’t ‘cook.’ Yet when combined, the Food Blend + Agar must be warm enough to prevent the Agar from gelling. Let cool until the temperature of the Agar is between 50C-60C (125F-140F). Now add while stirring constantly, the measured room temperature Food Blend to the Agar. The ratio of Food Blend to Agar should be 1:1. The mix should be thick at this point. Mix thoroughly and gently with a spoon. Pour onto a plate, dish, or for larger batches (like this medium sized batch), a non-stick cookie sheet. Spread evenly (but don’t be obsessed with making it perfectly even). Put it in the refrigerator making sure it remains flat and even.
Do more kitchen clean-up. If you allow the Food Blend or Food Blend + Agar to sit around, it becomes much more difficult to clean.
The next morning it can be cut up (like rubber) or chopped in a small food chopper to the desired size. I handle the food with a disposable plastic glove to avoid contaminating the food with my bare hand and to avoid getting this ‘stuff’ on me! If you made a medium to large batch, the chopper may become over heated. Simply stop chopping, return the Food Blend-Agar to the refrigerator and put the chopper into the refrigerator. Continue chopping 2+ hours later.
Store in multiple small snack bags which go into freezer bags (put multiple snack bags into one freezer bag). I usually put this combination into a sealed freezer container. Freeze it all. If spirulina powder was added in a good quantity, and meaty foods were included, this food would be a generic herbivore, omnivore, and carnivore food. Skew the ingredients to favor the type of fishes being fed BUT be sure to include ocean plankton and spirulina.9
I take a single snack bag out of the container and use portions of it to feed my fish. When the bag is depleted, I remove another bag from the container. The bag I remove I keep frozen. I thaw a portion in saltwater and filter if necessary (see NOTES below) just prior to feeding. I add it slowly to the display tank and feel great knowing my fishes are eating well.
- I feed this food for one feeding each day. The other (2+) feedings are store-bought frozen or freeze-dried foods (see above) or an In between food, and a rare pellet feeding.
- The chopper may end up making what I classify as 3 different sizes of food: small, fine, and very fine. Filter the food using used saltwater, through a baby brine shrimp net to get rid of the very fine pieces, just prior to feeding a portion to the fishes.
- If small pieces are the goal and a food chopper was used, there will be fine pieces in with the small. In this case, filter the food through a fish net or strainer with holes the size (and smaller) you don’t want. The fish net then contains the size you want to feed. This can be reversed – to remove pieces too large – in which case you feed what passes through the net/strainer, or even a second net/strainer.
- Since I use a fat supplement and a vitamin supplement in homemade food, I do not add supplements for the maintenance diet.
- The frozen food stored as suggested above, should still be good for 8 month when properly sealed/contained.
I’ve come across some methods or ‘tricks’ of feeding marine fishes. One situation is where a fish has been fed and is eating brine shrimp, but the fish needs to be weaned from this and get it eating other foods. The more or less obvious trick here is mixing the new food with the old food. The mix may start at 20% for a couple of days or one week, then 40% a couple of days or one week, then 60% a couple of days or one week, etc. until the fish is eating the new and better nutritious food.
Surprisingly, some fish refuse to eat the offered food simply because it is the wrong size. Many Clownfishes will eat only foods the hobbyist would think to be too small for them. Make sure the food is of the right size for the fish.
Besides size, sometimes the ‘food’ is in the wrong place. Our wild-caught ornamental marine fishes aren’t used to getting food from the top of the aquarium. For some Tangs, they may start eating if the proper seaweed or nori is rubber banded to a rock that sinks/sits on the substrate. After some time, they may ‘find’ the seaweed on a clip near the top of the aquarium.
Maybe the need arises that the fishes require some additional fat in their diet but prefer it to come from a more natural source (versus a fat additive like Selcon). I have taken some ‘regular’ food, like a frozen food the fish eats, and after RINSING the food, I add in decapsulated brine shrimp eggs (high in fat) and/or fish roe (eggs) or Fish Caviar® to it, on a plate. Another food is PE Frozen Calanus® when trying to bring out vibrant fish colors. Also, some other food too small for my fish to eat, may be dealt with in this manner: Let the mix dry out some, until it is all firmly stuck together – even just barely completely dry. Now section the semi-dried food and feed. The fish gets the benefit of the foods normally too small for it to eat.
In a ‘last-ditch’ effort to get a fish to eat, try feeding one of the live worms recommended in the LIVE FOODS section. If this fails, try live adult brine shrimp, but get the fish eating something else as soon as possible.
I had a penchant for keeping butterflyfishes, tangs, and some angelfishes. But these as well as most wild-caught marine fishes don’t find or get their food sinking from above. They must be trained to look for food floating or sinking. One way I’ve found is to get a piece of saltwater safe dead brain coral or saltwater safe plastic brain coral and press a bit of the food into it. Freeze it. Put into the QT directly from the freezer (it thaws quick enough at 78F and good water circulation). Fish will often find it, pick at it, and the food usually drifts around. They will often start feeding on the drifting food and now, drop some sinking/drifting food in, and they are trained! This may take as little as one attempt or 6 attempts, but it will sometimes work.
Many saltwater aquarium fishes are picky and fussy eaters. Getting them to be enthusiastic about the foods put into the aquarium can be a challenge. Sometimes an eating fish will stop eating. That is a big concern. A large (50%+) water change can sometimes get a fish eating. Sometimes feeding one of the live foods that move around a lot will get a fish eating. Check out reference 4. Varying the food may get the fish eating, but it also could be a sign of a problem.4 A healthy, previously eating fish can live without eating for a few weeks. After that time, the fish begins to ‘eat’ its own organs and thus has reached the point of no return.
Lastly (you thought this section would never end, didn’t you?), frequency of feeding. The feeding schedule doesn’t need to be fixed. Marine fishes eat constantly wherever and whenever they can. Their digestive track is set to digest constantly. So, when home, feed every hour or even more frequently. BUT the more frequently they are fed, the less quantity should be fed.
DON’T. . .
Most of the above is what should be fed or what to do. There are some “don’ts’, however.
Please don’t feed romaine (or any other kind of land) lettuce. There’s really no reason to, considering the readily available sun- or air-dried seaweed and nori. Romaine does have some useful nutritional value, e.g., HUFA content, but nowhere near the high HUFA content and nutritional value of ocean seaweed.3 From the 60’s to the 90’s hobbyists were told to feed Romaine lettuce to their carnivores, but now we know better. Besides this, we now know that algae is needed by marine fishes to make their own fish oils10.
Don’t feed land products to marine fishes.
Don’t feed cooked or heated foods. For example, seaweed and nori need to be air or sun-dried, not heated/roasted dry.
Don't feed adult brine shrimp (unless gut loaded and then only rarely). Know that brine shrimp (beyond the ‘baby stage’) is low nutrition. Wean fish ‘hooked’ on adult brine shrimp or live adult brine shrimp as soon as possible and don’t feed often. When adult brine shrimp is fed, the brine shrimp should be at least gut loaded with Omega 3 or HUFA, or spirulina.
Don’t feed freshwater plankton. There is an ample supply of ocean plankton (freeze-dried is safest).
Don’t feed freshwater plants or animals. I do make the exception of whole freshwater clams/mussels, garlic juice, freshwater snails, and some live foods.
Don’t feed foods that are not explained or qualified on the package. For example, the ingredient might be “plankton.” Since there is such a thing as freshwater plankton, be sure it is ocean plankton.
Don’t feed any food with undisclosed contents/ingredients.
Don’t feed beef heart. North American people don’t eat beef hearts, so in the 1960s they were trashed or added to dog food – until someone got a brilliant idea. Bought for $.12 (12 cents)/lb this person ground it up and froze it in flat bars. Through clever marketing to tropical fish enthusiasts it was the ‘thing to feed’ to their fish – at about $1.00/ounce ($16/lb). Marine ornamental fish don’t eat land animals (or their parts). With so many much better alternatives available, pass this one up.
Don't believe the ‘name’ on the product. Read the ingredients list. Products claiming to be for marine fish should be investigated as to what it contains: If the first three ingredients don't contain at least 2 marine sources, keep looking for those that do.
Don't let fish get into the habit of eating one or even three kinds of food. Not only offer different foods, but also change food makers. And finally, on this subject, remember: a varied diet doesn't mean providing a variety of wrong foods, it means providing a variety of the right foods! The best time to train fish what to eat is while it is alone in quarantine waiting to be added to the display tank. This is one of the very important reasons to quarantine all new fish.
Don’t feed a vitamin supplement that doesn’t list each vitamin and the vitamin quantity either in the ingredients list or online. Don’t feed any vitamin that doesn’t match or exceed the vitamin list of Vita-Chem8.
One of the most expensive and difficult vitamins to provide in prepared foods is Vitamin D. Read closely to see if that 'vitamin enriched' product contains this vitamin, as well as A and a stabilized C.
Even though the food says it contains vitamins, it doesn't replace adding a vitamin supplement recommended above.
Coaxing a new fish in the QT to eat is a different story and the above may or may not apply until the fish is at least eating regularly. At first, feed whatever the fish will eat then offer alternatives as soon as possible.4 See the TRICKS section.
The right diet with supplements can provide ornamental marine fishes with their natural resistance, together with excellent water quality, and in an un-stressed (e.g., space, other fish(es)) environment. This brings us back to the introduction. Saltwater aquariums contain bacteria–we can’t add ‘sterile’ fish to the display tank. Such conditions and diseases that a healthy fish will fend off include bacterial infections (cloudy eye), Popeye, secondary bacterial infections, internal bacterial infections, septicemia, blindness, weakened immune response, deteriorating fins, Lymphocytosis and a host of others. A healthy fish fed good foods and supplements will also resist Mycobacterium marinum infections even when this bacteria is in the aquarium. A properly nourished fish will heal from a minor injury faster, too.13 BUT. . .Know that a good diet and healthy fish does not mean it will prevent it getting nor survive Marine Ich (Cryptocaryon irritans), Marine Velvet, fluke or worm infections, and an obligate parasite attacking in the close confines of an infested aquarium.
An ounce of prevention… I hope this post provides an in-depth view of fish nutritional needs, and that the reader has found a new perspective of good marine fish nutrition.
1 The Nutritional Needs of Saltwater Aquarium Fish
2 The Effects of Beta Glucan on Fish Immunity
3 In Depth Comparison - Seaweed v Romaine Lettuce
4 Tips for Getting a Fussy Fish to Eat
5 The fate and risk of nontuberculous mycobacteria in the water supply system: a review
6 Brine Shrimp
7 FDA on Fish Foods Although written for human consumption, there is valuable information on the selection and storage of fish.
8 There may be other vitamin supplements, liquids and water-soluble solids to choose from. If not using Vita-Chem, then choose one with multiple vitamins from more or less marine sources (with Vitamin D, A, B1, B2, B6, and stabilized Vitamin C).1 Make sure whatever vitamin supplement is chosen, insist on a vitamin content breakdown and know exactly what vitamins are present, then compare that to Vita-Chem’s vitamin list.
9 Marine fishes need algae and/or plankton to make their oil. See this reference under the section Nutritional Details.
10 Seaweed Nutritional Information
11 Removal of Trace Elements by Activated Carbon
12 Disadvantages of Using Feeder Fish Goldfish in particular is a bad choice to feed ornamental marine fishes.
13 One of Many Studies on the use of Beta Glucan to help in the healing process
Revised March 12, 2023; June 11, 2023