How To Culture Micro Algae and Rotifers

Introduction

How many of you marine aquarists have had a pair of clown fish spawn, or a shrimp release a few hundred larvae, in your marine tank? Some of you may have tried to feed the larvae on freshly hatched brine shrimp naupii, crushed flake, or some liquid concoction, probably with very little success. I have been a professional fresh water tropical fish breeder for a number of years. With the help and encouragement of Billy Hickman (M G Marines), I have set up a small marine fish room with the intention of breeding some of the easier fish and shrimps. With my background in fresh water tropicals I knew that the feeding of the larvae and fry would be the most critical element in the successful raising of tropical marines.

Culturing

First of all we need to create a continuous supply of single celled micro algae. Please note this is not the same as the hair algae or blanket weed which cause such unsightly problems in our aquariums and pools. The single celled algae are classed as phytoplankton, they act in a similar manner as terrestrial plants, using light to give them energy to convert dissolved nutrients into more complete carbon molecules. In the sea the light comes from the sun and the nutrients are found in inexhaustible quantities. In our artificial environment the light comes from 2 domestic fluorescent tubes running 24 hours a day and the nutrients come from a special algae fertiliser which is added to your freshly made marine salt mix to become your algae culture solution. By gradually adding your algae culture solution to a live algae culture you can create your own continuous supply of micro algae using clear 2 litre pop bottles as containers. The pop bottles are obviously a food grade plastic, they allow good light penetration, are basically free and when coated so thickly with algae that it stops light penetrating they can be disposed of in the bin. I use a 5 litre mineral bottle to hold my micro algae culture solution. I add the dry salt and liquid fertiliser to the 5 litre bottle, fill it with R.O. water, let it stand for 24 hours and it is then ready for use. Fully developed micro algae cultures can be fed directly to your reef tank as a food source for all your filter feeds, just turn the protein skimmer off for a few hours. The second stage in the process is to culture the marine rotifers. These are very small animals (zooplankton), just visible to the naked eye and approximately 1/3rd the size of freshly hatched brine shrimp naupii. You can culture rotifers in any wide-mouthed jar or fish tank. When fed correctly these animals reproduce so proficiently that 1,000 rotifers can become 1,000,000 in 8 days. By adding your micro algae culture (which should be dense dark green in colour) to your rotifers you give them food and also increase their culture volume, making room for their increasing population. As the rotifer culture clears just add more micro algae culture. As soon as possible start a second and then a third rotifer culture. I recommend that you maintain 2 rotifer cultures and 7 micro algae cultures. They should be all bubbling nicely with rigid airlines going to the bottom of each culture container, just keeping the culture turning over (NOT BOILING UP AND FOAMING). The rotifer culture medium can be poured through a rotifer sieve (much finer than a brine shrimp sieve) and the contents of the sieve added to the tank in which you are raising your fish or shrimp larvae. It is these well-fed rotifers that will be the sole food supply for your fish and shrimp larvae up to their metamorphism, after which you can start to carefully introduce freshly hatched brine shrimp and powdered foods. Rotifers can also be fed directly to your reef tank, again to feed filter feeders and inverts. This has been a brief overview of the culture of micro algae and rotifers. For a more detailed description of raising clown fish and also the culture of micro algae, rotifers and brine shrimp I recommend you read Joyce D Wilkersons book Clownfishes published by Microcosm. LIVE MICRO ALGAE CULTURES, LIVE ROTIFER CULTURES AND THE MICRO ALGAE FERTILISER ARE AVAILABLE FROM KINGSWINFORD AQUATICS. If anyone requires further information, or exchange information/ideas, please contact Charles on 01384 270926 (preferably before 10.00p.m !!)