Nutritional values

[mjw011689]

Curious to see everyone’s thoughts on this… do we have any information that says specifically what percentages of protein or fiber or ash etc. that our fish should be getting? Obviously it’s different fish to fish, but say tangs for example, what should I be looking for when purchasing algae sheets or other foods for that matter? My tangs get a combo of algae sheets (usually rods or Julian sprungs), algae pellets and formula 1 flake. Occasionally they’ll get mysis but not super often.

But how do we know whether one food is better than another aside from someone saying they like this or that? Not that there’s really too many options when it comes to stuff like seaweed.

 

[Cali Reef Life]

Heres a good video to watch to get a baseline. Not a beginner but still useful knowledge. Also a good article below the video.

Tips for Choosing the Right Fish Food - Beginner's Guide Ep: 36

Choosing high-quality fish food and feeding your fish correctly will help your fish thrive in captivity and look great while doing it.

www.bulkreefsupply.com

Fish and Coral Food FAQs - What To Feed, How Much, and When!

Learn to feed your saltwater aquarium like a pro as we answer some of the most frequently asked questions about fish and coral food.

www.bulkreefsupply.com

 

[ISpeakForTheSeas]

TLDR summary (the footnotes version) at the end.

As a quick note before addressing the rest of the question, we call tangs herbivores, but they're not really - they're omnivores that lean more carnivorous:

As mentioned, an urchin may take to eating dead/dying fish, but they don't generally go for live fish.


With regards to the herbivore vs. omnivore vs. carnivore thing with urchins (and keeping in mind that all species of urchins have different diets) - I had a similar conversation a while ago about a specific species of starfish, so here's my two cents on the matter:

We tend to think of herbivores and carnivores in black and white terms - thinking that something is either a pure herbivore, a pure carnivore, or an omnivore. In reality, though, these terms are more of a sliding scale/spectrum than separate categories, and only the extreme ends of the spectrum have "pure" diets.

For example, cows (well known for being herbivores) have been known to sometimes eat insects (or even mice/in extreme cases, chickens) - this would, by strict definitions, make them omnivores, but they're not considered to be such. Similarly, carnivores eat the guts of their prey, and often end up eating undigested plants in the process - but they're still carnivores. Frugivorous (fruit-eating) toucans also have been known to purposefully eat insects during their breeding season for extra protein, so they may be considered omnivores during their breeding season, but they're not considered omnivores during the rest of the year.


So, a better way to think about herbivore, omnivore, and carnivore is like this:

-Does the species need one or more specific feeds to survive, and, if so, which category/categories are these feeds from?

-On average, what percentage of the species' diet comes from which category? Does a substantial portion of the diet consistently come from more than one category?

-Is the ingestion of each food item purposeful, or incidental? (i.e. Does the species purposefully seek out foods from a specific category when they have the chance to do so, or not? Does it happen to eat foods from a specific category while consuming foods from another?)

-How does the species' diet change throughout the year? (Edit: How does the species' diet change throughout its life? [some species have drastically different diets at different life stages; for examples, Crown of Thorns Starfish are herbivores as larvae/juveniles, but carnivores as adults]).


Pretty much all species will branch out a little from their natural diet on occasion (hence why we sometimes get tangs eating corals, though it is rare), so there are frequently exceptions to the above, but these questions should get you the big picture.

To apply this to tuxedo urchins:
-If the species only requires one food (algae) to survive, then it's likely an herbivore.

-If the majority of a species' diet consists of foods from only one category, and only an insignificantly small portion of the species' overall diet consists of a food outside of that category (say, like a dying wrasse), then it's likely an herbivore.

-If the ingestion of foods from outside of its primary food category is incidental rather than purposeful, then it's likely an herbivore (in this case, there's a good chance the ingestion was purposeful - so one point for the omnivore category).

-Tuxedo urchin diets don't really change drastically throughout the year, so no change here.


So, using the criteria above, tuxedo urchins are herbivores, but they're not pure herbivores (and neither are herbivorous fish, which are really more omnivores, but eating significant portions of algae is uncommon among fish, so they're considered herbivores).

An example of a pure herbivore would be an Elysia species Sacoglossan slug, which only feeds on macroalgae. Several nudibranchs are examples of pure carnivores.

So, most creatures are technically omnivores, but may be considered as herbivores or omnivores depending on the criteria above.

Alright, now on to the question:

Curious to see everyone’s thoughts on this… do we have any information that says specifically what percentages of protein or fiber or ash etc. that our fish should be getting? Obviously it’s different fish to fish, but say tangs for example, what should I be looking for when purchasing algae sheets or other foods for that matter? My tangs get a combo of algae sheets (usually rods or Julian sprungs), algae pellets and formula 1 flake. Occasionally they’ll get mysis but not super often.

But how do we know whether one food is better than another aside from someone saying they like this or that? Not that there’s really too many options when it comes to stuff like seaweed.

We do have some info on that, but it's typically found for fishery fish (so, kitchen table food fish) - specific info for various fish in the hobby is limited.

Personally, I look at data available on successful aquaculture and rearing diets for a variety of different species (including some fishery fish) and compare their info to find the commonalities between them. From doing that, I reached the conclusions below (the big picture is relatively easy; the small details get tricky even when working with a single species):

Given that most aquaculture places use one, stable diet (using one feed and not switching feeds) for the broodstock of each species they work with and that fish need to be in basically peak physical condition to breed successfully, I'd say that a variety of feeds isn't always the best nutritionally.

One, good, quality feed is likely going to be better in a lot of situations.

That said, the best feeds for fish generally do have a good variety of ingredients (typically containing things like fish, crustaceans like shrimp or krill, bivalves, and different kinds of algae); the key is using ingredients that meet the various nutritional needs for most fish in the right quantities - as mentioned, some fish will need more/different kinds of meaty foods, some need more algae or a wider variety/different kind of algae, some may need sponges in their diet, etc., but in a reef tank setting with a wide range of fish, it's probably easier to feed a good quality "general/carnivore" fish feed and supplement it as needed for those fish with special dietary requirements (this is most commonly seen here when people feed frozen/pellets and supplement it with algae by offering nori to accommodate herbivores).

As a quick note here, not all ingredients (fish, crustaceans, bivalves, algae, etc.) are equally good - each species of fish, crustacean, bivalve, algae, etc. has its own nutritional profile/makeup; some fish will benefit more from some species than others (lion king discusses this in a few of their threads on predator nutrition here on R2R and Jay touched on this a bit above), but a few generalizations can be made (for example, salmon is almost always a good choice, same with clams of just about any kind, and with Ulva and Graciliaria and Halymenia macroalgae from what I've seen). The ingredients can also have a noticeable impact on the coloration of fish (which is why a lot of companies like to note that their feed contains astaxanthin and spirulina).

So, when considering feeds, as Jay said:

The diet must also have the proper balance of fats, proteins, and carbohydrates, as well as the proper amount of vitamins and minerals.

From what I’ve seen, for the best health in fish, you want a variety of good ingredients, high protein (50%+ minimum by dry weight, preferably closer to 60%+), and a moderate amount of fat (10-15% by dry weight, preferably closer to 13 or 14%).

You want to consider the dry matter basis analysis for the protein, fat, etc. content of a feed (i.e. you want to look at how much protein, fat, etc. is in a feed once you get rid of the moisture in the feed - this is especially important for evaluating frozen feeds), and you want to consider the ingredients of the feed (too many grains and/or carbs is a no go - fish aren't designed to handle grains and carbs like humans do - and you want a good variety of ingredients to try and ensure that the feed contains the vitamins and minerals your fish need).

With regards to the whole foods vs. meals and starches: whole is generally ideal, but meals may be made using the whole fish/squid/etc., depending on how it's processed. If it is made with the whole item, then the meal could be just as good as the whole (though it's not necessarily, which is why I say whole is generally ideal). The real issue with meals is that you don't know what all goes into them - it could be the whole fish and a bunch of healthy fish species, it could be basically all the trash parts of nutritionally worthless species, or it could be anything in between.

The flours and starches basically provide calories that the nutrient dense meals, oils, etc. in the feed may lack while helping the pellets stay together in the water (so it's meant to provide the energy while the rest of the food provides nutrition), but you're right that these are not healthy in excess. The excess carbs from too much starch have been shown to cause a variety of different health issues and weakened immune systems (dependent on fish species, natural diet, etc.).* So, starches in moderation are fine, but when overdone, they definitely can cause issues. Whether or not TDO and similar pellets have enough starch to cause these issues is a fair question that would require some pretty intensive research to figure out. Based on the results TDO gives, I would assume that, if it has too much starch, it only has slightly too much (meaning that real issues likely wouldn't be seen for years).

My understanding is that newer (superior) pelleting methods don't require as much starch to keep them together as older methods do, but I've heard that older methods are still largely the norm for the fish keeping industry.

For the other aspects of good nutrition in feeds, look at dry matter basis protein and fat contents; the kinds of fats in the feed; and other nutrients, micronutrients, vitamins, minerals, etc. in the feed, such as thiaminase and vitamin B1 (these two examples are particularly important to be aware of when dealing with predatory fish).

*Source:
https://www.researchgate.net/public...growth_glucose_metabolism_and_hepatic_enzymes

Unfortunately, foods that have good amounts of protein and fat rarely contain good amounts of algae (algae isn't really high in protein or fat, so adding a significant amount to the meaty feeds really lowers the percent totals). Personally, for best health, I would take a really high quality meaty feed and add a good variety of algae to supplement it/add an algae heavy feed to supplement it to get a good balance for any herbivores in the tank.

Personally, my suggested feeds would be as follows (I apologize, I haven't looked into frozen algae-heavy feeds enough to have one that I would suggest at this point; I'll have to remedy that):
Frozen (Meaty) - LRS Reef Frenzy, Hikari Mega Marine, then Rod's Original.

Pellets (Meaty) - Otohime, then TDO Chromaboost.
Pellets (Algal) - NLS Marine Fish Pellets (has 8 types of algae and one terrestrial plant).

LRS has a higher protein content while Rod’s has higher fat (~59% protein and ~13% fat for LRS Reef Frenzy, ~53% protein and ~15% fat for Rod’s Original).

As a side note here, I'm actually quite impressed by Hikari's Mega Marine line there; I haven't looked at that line in depth before, but it says it has a 75% dry protein content and - depending on the specific blend in the line (regular, angel, and algae) - a 10-15% dry fat content with solid/good ingredients. The only thing that I see that I wish they had in the mix is some kind of fish (LRS Reef Frenzy has Ocean Perch and Whitefish, for example) and, for the algae blend, some kind of bivalve or two. For comparison, LRS Reef Frenzy - according to their lab test results on their site - has 59.1% dry protein and 12.7% dry fat.

An explanation of dry matter basis:

With regards to the moisture and protein content, when looking at foods for pets (fish, cats, dogs, etc.), it's a good idea to look at the dry matter basis of the guaranteed analysis. To state it simply, frozen foods and wet foods show super low protein and fat contents on their guaranteed analysis labels when compared to dry foods - this isn't because they're lower quality or less healthy, it's just that they have more moisture in the mix. To compare apples to apples protein and fat of frozen/wet vs dry foods, you take the dry matter basis of each factor (protein on its own and fat on its own once you've accounted for moisture).

For example, San Francisco Bay Brand Frozen Spirulina Brine Shrimp lists the following guaranteed analysis:
Crude Protein (Min): 3.7%
Crude Fat (Min): 1.2%
Crude Fiber (Max): 1.6%
Moisture (Max): 94.8%
Ash (Max): 0.2%
Phosphorus (Min): 0.1%

Looks very not nutritious. But, when you account for the moisture by taking the dry matter basis, you realize that that 3.7% protein is 3.7 out of 5.2 (the actual amount of food in the pack; i.e. the percent of the food that isn't moisture like the water used to hold the frozen food together or to keep the meat in the cat food can fresh). So, looking at the dry matter basis, 3.7/5.2 = 0.71 (rounded for simplicity's sake) - times this by 100 to get the percentage and you get a dry matter basis of 71% Crude Protein content. So, while it looks unhealthy at first glance, when you look at just the food in the food packet and not the moisture plus the food, you find out that the food is actually fairly healthy.

Because of this, a lot of frozen/wet pet foods look worthless at first glance, but some of them are actually top of the line foods when compared to dry foods this way. The only real downside of frozen/wet foods is that - because of the high moisture content - you might not always be getting as much food pound for pound as buying dry (i.e. one lb of dry food is going to have a lot more actual food in the container than one lb of frozen/wet food because of the lower moisture content). This really just means that frozen/wet foods are generally more expensive.

TLDR: Frozen/wet pet foods look unhealthy, but, accounting for moisture, they're usually high quality. They're just expensive too.

Alright, the TLDR:

Look at dry matter basis protein and fat contents; the kinds of fats in the feed; and other nutrients, micronutrients, vitamins, minerals, etc. in the feed, such as thiaminase and vitamin B1 (these two examples are particularly important to be aware of when dealing with predatory fish).

-A variety of good ingredients (things like salmon, clams, Ulva, etc.).
-High protein (50%+ minimum by dry weight, preferably closer to 60%+).
-A moderate amount of fat (10-15% by dry weight, preferably closer to 13 or 14%).
-Avoid excess starches, grains, and carbs (important with pellets and flakes).

 

[mjw011689]

Thanks for all the info! Took a while to get through it but there’s a ton of great info there.

As far as tangs go (include foxface since I’ve got one of them too), I’ve always heard they’re mostly herbivorous, if not completely. Obviously they’re gonna snag some meat here and there, but overall, are they not mostly herbivorous?

To keep it short, it seems like LRS reef frenzy or hikari mega marine are the way to go with frozen foods?

For pellet, do we have any new info on whether TDO has too much starch?

I’m now seeing that the foods I’m feeding do NOT have that high of protein or fat. Now I’m looking at switching back to LRS as a primary food supplemented with algae sheets for the tangs… possibly a small amount of TDO throughout the day. My only concern is that the tangs get enough algae

 

[ISpeakForTheSeas]

As far as tangs go (include foxface since I’ve got one of them too), I’ve always heard they’re mostly herbivorous, if not completely. Obviously they’re gonna snag some meat here and there, but overall, are they not mostly herbivorous?

This made me double check myself, and it (unsurprisingly) seems to vary from one species to another, but I must say I do seem to stand corrected there (which I'm actually grateful for, both because it corrects a misunderstanding of mine, and because it gives me more to research later; it seems each species has specific kinds if algae they prefer to eat off of specific surfaces, so that'll be fun reading for me).

Anyway, it seems most are omnivorous leaning herbivorous, with a few (but not most) Acanthurus (and possibly Zebrasoma) species being thought to be pretty much exclusively herbivorous,* and a few (like the Pacific Blue Tang**) being primarily carnivorous.

To keep it short, it seems like LRS reef frenzy or hikari mega marine are the way to go with frozen foods?

For pellet, do we have any new info on whether TDO has too much starch?

Yeah, LRS Reef Frenzy and the Hikari Mega Marine line would be my feeds of choice (LRS has a lot of evidence backing it; I haven't seen evidence from Hikari yet, but I don't know many if any people using it as a staple at the moment).

Unfortunately, no new information on the starch.

I’m now seeing that the foods I’m feeding do NOT have that high of protein or fat. Now I’m looking at switching back to LRS as a primary food supplemented with algae sheets for the tangs… possibly a small amount of TDO throughout the day. My only concern is that the tangs get enough algae

LRS is great for most fish; I would absolutely supplement it with algae even for non-herbivorous fish. For the tangs, most species seem to eat a large quantity of algae (they're algae-eating impact is noted as being disproportionately large for their body size in one of the linked articles), and most seem to prefer green algae, but it does vary from one species and genus to another.

I'll have to do some more reading there for sure, but what species are you working with? That could give you a place to start for tailoring a specific diet to meet your fishes' needs.

*Sources:

https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.11070

https://onlinelibrary.wiley.com/doi/full/10.1002/edn3.247

**Sources:

Paracanthurus hepatus summary page

www.fishbase.de

https://onlinelibrary.wiley.com/action/oidcStart?redirectUri=%2Fdoi%2F10.1111%2Fjwas.12426

Edit: Another thought from another article - I'm curious if most/many tangs are primarily herbivorous due to actual nutritional requirements, or if it's due to a lack of available meat (either way, I've got some reading to do). The article that spurred the thought:

Facultative scavenging feeding habits in Acanthurus chirurgus (Bloch, 1787) (Acanthuriformes: Acanthuridae)

The family Acanthuridae is a key component of coral reef ecosystems as it controls macroalgae biomass buildup. During routine monitoring of benthic communities in the Mexican Caribbean, we observed unusual behaviour of a group of Acanthurus chirurgus, ...

www.ncbi.nlm.nih.gov

 

[mjw011689]

I'll have to do some more reading there for sure, but what species are you working with? That could give you a place to start for tailoring a specific diet to meet your fishes' needs.

I’ve got a purple tang and a blue hippo tang for now. Eventually that may get added to when an upgrade happens.

 

[ISpeakForTheSeas]

I’ve got a purple tang and a blue hippo tang for now. Eventually that may get added to when an upgrade happens.

So, for the purple tang (Zebrasoma xanthurum):

"The fish consumed over 30 different species of algae, the dominant dietary algae genera differing among fish species: Hypnea spp. and Phylophora spp. were most frequent in A. sohal, while Feldmannia spp. and Pterocladia spp. were dominant in Z. xanthurum (see Table S1 in Supplementary material)."*

Feldmannia is a brown algae, and Pterocladia is a red algae; so those seem to be the preference, but purple tangs are noted for being pretty varied with their diets - so I'd try making sure it gets some red, brown, and green algae.

(I'd need to do more research on the individual algae genera to look at specific nutritional compositions and see what some comparable kinds of algae that are readily available on the market may be, but given the purple tang's generalist nature, just ensuring it gets some red and brown algae with some supplemental green algae is probably good enough for now.)

Also of note:

"Herbivorous fish consume around 20% of their body weight per day compared to only 3%–4% for carnivorous fish (Horn 1989)."*

The purple tang's weight was estimated at 250 grams.*

"feeding preference was generally more spread out across a range of substrates in Z. xanthurum, led by EAT on rock (Figure 5)."**

EAT standing for Epilithic Algal Turfs - basically, purple tangs feed on algae growing on a variety of surfaces, but they show a preference for algae on rocks.


For the blue hippo tang (Paracanthurus hepatus), A.K.A. the pacific blue tang;

"Feed on zooplankton and occasionally on algae (Ref. 9710, 48637, 27115, 83665)."***

"Pacific blue tang broodstock were fed a varied diet to apparent satiation three to five times daily. The diet consisted of a mixture of a commercially prepared seafood blend (LRS Fertility Frenzy, Larry's Reef Services, Advance, NC, USA); fish eggs (LRS Fish Eggs, Larry's Reef Services); frozen mysis shrimp, Mysis diluviana (Piscine Energetics, Inc., Vernon, BC, Canada); and a commercially available 1.7-mm extruded pellet ([EP1 – 46% crude protein, 16% crude fat, and 2% crude fiber], TDO Chroma Boost, Reed Mariculture, Inc., Campbell, CA, USA)."****


*Source:

https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2435.2007.01330.x

**Source:

https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.11070

***Source:

Paracanthurus hepatus summary page

www.fishbase.de

****Source:

https://onlinelibrary.wiley.com/action/oidcStart?redirectUri=%2Fdoi%2F10.1111%2Fjwas.12426

 

[mjw011689]

Now to throw a wrench in there, what about adding stuff like selcon? Is it as beneficial as claimed? Should it be added to every feeding?

 

[ISpeakForTheSeas]

Now to throw a wrench in there, what about adding stuff like selcon? Is it as beneficial as claimed? Should it be added to every feeding?

That's a bit of a murky area at the moment - I have seen Selcon used helpfully to enrich rotifers to rear specific larvae before, but I don't know that I've seen it used helpfully with adult fish.

It's basically just a relatively healthy fat source supplement, so if you think the diet is lacking in healthy fat for some reason, then it may be good to add, but otherwise I don't know that it would be helpful.