Alternate food for rotifer culture

Mike N · Jun 15, 2020

I stupidly left the food for my rotifer culture outside the fridge last night.
I figured it was no longer good and tossed it.
Now I have no food for my rotifer culture and I'm wondering if anything else can be used as an alternative in a pinch.
Would Reef roids or Reef chili sustain the culture until I can get the proper food again?

Big G · Jun 17, 2020

Bump

Mike N · Jun 17, 2020

Big G said:
Bump

Thanks.
I have actually been using reef roids to feed my culture for the last 3-4 days until I can get RGcomplete again.
Surprisingly, the culture is doing just fine on the roids

I did find some information on the web about other alternatives that seem to work. Here it is for anyone that finds it useful. Selcon was a particularly surprising addition to the list.

Excerpt from: reefs.com magazine

Alternatives to live phytoplanktons
Can we raise fish larvae with out having to set up and maintain an algae culture system? Absolutely, more and more commercially produced substitutes are becoming available which will either supplement or potentially even replace live phytoplankton cultures.

The first alternative to live phytoplanktons is cryopreserved phytos. There are a few companies that currently supply concentrated phytoplanktons in commercial quantities. One such company is Inland seafarms Inc. (cryopreserved phytoplanktons can be purchased in hobbyist quantities from www.brineshrimpdirect.com). This company provides many different cryopreserved phytoplankton species along with their respective HUFA analysis. Next is Innovative aquaculture, this company provides monocultures of N. Oculata and Chaetoceros and mixed formulas of both. Due to the mixture formulas these products can be used as a nutritionally complete first diet. A third company is Reed Mariculture, this company supplies mono and mixed cultures of cryopreserved phytoplankton, and even provides a wonderful mixed of three phytoplankton called “Tahitian blend” which contain N. Oculata, T-Iso (Tahitian strain), and in proper ratios to ensure a wide distribution of HUFAs (www.brineshrimpdirect.com) sells Reed Mariculture’s cyropreserved phytoplanktons). A key feature about the cryopreserved phytoplanktons is there remarkable shelf life. According to company information, one can store these products at 40C for up to one yr w/o loss of nutritional value. When stored at –200C Inland claims a 2-yr shelf life. While these are manufacturer’s claims, ongoing studies are being performed to determine nutritional profiles after defined storage periods. Cryopreserved phytoplankton is an excellent alternative if you are in need of a large volume of greenwater. These products can be used for rotifer and nauplii cultures, with however one limitation. These products are dead phytoplanktons and as such contribute to water fouling immediate upon addition to the water. Therefore, be aware that use of these cryopreserved products will require you to do frequent water changes in your prey item cultures to maintain proper water
parameters.

A second alternative is a product called spray-dried cells of S_chizochytrium_ sp. Aquafuana marine Inc produces two enrichment products based on this concept. Algamac 2000 and RotiMac. Both AlgaMac and RotiMac can be used as direct food substitutes for rotifers and nauplii, or as a supplement to other foods. RotiMac has HUFA levels of 0.3% (EPA) and 19.6% (DHA) while AlgaMac has EPA levels of 0.6% and DHA 24.0%. RotiMac is actually sold as a food substitute for rotifers, whereas AlgaMac is considered as an enrichment product for rotifers and artemia. These products have found success in the shrimp aquaculture arena. One benefit of using these products is that unlike fish-oil based enrichment media RotiMac and AlgaMac can be used directly in your larval tank. Similar to using the other food substitutes, water fouling can be a serious problem, and one must keep a cautious eye on their use. The shelf life of these two products is listed as 9 months in a cool dry
location.

A third food substitute is a fish oil based enrichment. These Selco/Selcon based medias (both liquid and dry forms; (Culture Selco, Roti-rich, Rich, Rich Advance, Algae Rich) are high in Omega-3 fatty acids and are particularly good for the final stages of rotifer and Artemia nauplii enrichment prior to feeding to your fish larvae. Approximately 4-24 hrs before you use the rotifers or nauplii add these Selcon/Selco type products to the water. After enrichment, collect the prey items and feed directly to your fish larvae, do not carry over Selco enriched water into the larvae tank; these products will quickly foul tank water. As with any enrichment, as soon as rotifers/nauplii clear their gut of any food item they are inadequate as a food item. Greenwater can aid in keeping rotifers/nauplii enriched over a period of time in the culture tanks, but additional care and maintenance will be required to prevent water quality issues in your grow out tanks when using these fish-oil
based products. Interestingly, many manufacturers suggest that these products can be utilized as a direct microalgae replacement, and while they do provide adequate nutrients to the rotifers, they are best utilized when performing batch cultures. The main reason is that one can remove the fouled water between each batch, and clean the container to remove any oily film or residue.

A fourth option is to use Martin Moe’s V-8 technique. Initially described in “Breeding the Orchid Dottyback” (Moe 1997), this technique relies on the use of the product V-8 juice as a nutritional supplement. His description utilized a few mls of V-8 juice and selcon to boost levels in prey items. While this is a unique and interesting alternative, I’m not sure what the DHA or EPA levels of V-8, or the nutritional value of the rotifers that were fed V-8; however, Martin Moe was successful using this method and as such it should not be discounted. Again, as a reminder when using products like these, concern for water quality should be paramount, as they will quickly foul your water.

Interestingly, Rotifers can alternatively be cultured solely by being fed on bread yeast. A culture can be established which utilizes 2.5-20 gms of yeast /gal of tank water inoculated w/ 10-20 rotifers/ml. The bread yeast, dissolved in fresh water, is added twice daily at a ratio of 1 g of yeast to 106 rotifers. After 7 to 10 days, the rotifer density usually exceeds 100 individuals per milliliter. At this stage, they can be completely or partially harvested as feed for larvae.

Larval culture is possible without live phytoplanktons, but it may not be the best choice. Cryopreserved phytoplankton offer the closest alternative to live phytoplanktons, followed by the spray-dried products. Care must be exercised when using these products, as they will quickly foul small volumes of water. Lastly, if you do use a phytoplankton substitute consider adding an enrichment type substitute (like selcon) to ensure a well-balanced meal.

Hopefully after reading this column I have provided you with enough material and ideas to start your own home culture of both phytoplankton and rotifers. I will end by saying that some fish larvae are too small to consume rotifers as a first food. Therefore, we must consider food items smaller than rotifers as their first food. Fortunately, there are a number of marine organisms that are much smaller than rotifers and can be cultured at home in vast numbers. These are ciliates.

There are about 8,000 species in the Phylum Ciliophora. The name Ciliophora means “bearing eyelashes” and this is a good description of the tiny, short, whip shaped flagella that cover most species of ciliates. There are many species capable of living in the marine environment, both planktonic and benthic, and some, particularly in the genera Tintinnopsis and Euplotes, have potential as food organisms for very small fish larvae and perhaps invertebrates as well. Ciliates reproduce by mitotic division and so in the proper culture environment, reproduction can be rapid. One of the key features of any larval food organism is that it must be capable of rapid reproduction and must be able to sustain dense cultures in order to supply the quantity of food required to feed large numbers of larvae. Ciliates certainly fill these requirements. Other requirements, however, such as nutritive value and acceptability by larval fish as food organisms, are not as encouraging. Next
month we will take an in-depth look at the techniques of rearing ciliates for fish culture and perhaps other aquaristic uses.