The fry of egg-layers are usually first fed on Infusoria, this is by enlarge an obsolete term, but is still used by fishkeepers to represent a variety of minute or microscopic animal and vegetable organisms, which develop in an infusion of decaying organic matter.

Infusoria cultures can be prepared quite simply; the spores are airborne so there is no need to obtain starter cultures. All you need is an open jar three quarters full of aquarium water, to which you add either a small amount of potato (lightly boiled may be of benefit), banana skin, dried lettuce leaves, or hay, allow this to stand for about a week, after which it will become cloudy with Infusoria.

When it is time to feed the fry just pour a little of this cloudy water into the aquarium, then top up with aquarium water again. If you have a few of these cultures on the go at once it will give you a constant supply of Infusoria.

Brine Shrimps are marine shrimps, which are also available in dried form; they can easily be cultivated from eggs available from some aquatic shops. They will be supplied in sealed airtight containers and it is imperative that they remain in a dry and cool place; otherwise, if they get damp they will fail to hatch.

Take a one litre plastic bottle and half fill it with tap water, the water should be kept at 75 degrees F (24 C), add to it one and a half teaspoons of salt (aquarium or sea salt preferably), then add a quarter of a teaspoon of the eggs.

You will then need to place a piece of airline into the bottle and attach the other end of the airline to an airpump. Run the airpump, which will circulate the eggs in the bottle, after about 36 hours the eggs will have hatched and the shells will float to the surface, at this point you can remove the airline.

Wait for a further 30 minutes and you will see the newly hatched Brineshrimp at the base of the bottle, place a plastic tube into the bottle and siphon the minute shrimps through, either clean dry linen, nylon, or paper towel. They can now be washed in fresh water and fed to the fish.

Microworms are a minute worm, also bought as a culture; you may be able to obtain a starter culture from another aquarist. Microworms feed on the surface of cereal-based foods, therefore you will need to mix up some oatmeal with a little water (porridge), be sure to only use water.

Let the mixture cool then spread a layer of it, about 1cm (0.4inch) thick, onto the base of a container or saucer, take a small spoonful of the culture and place it onto the porridge, put a lid or cover (which must have a few small air holes in it), over the container, and keep it in a warm place 70 - 75 degrees F (21 - 24C).

After a few days the worms will have multiplied and will be climbing around the sides of the container, you can wipe these off with a small brush and feed them directly to the fry. You will need to start fresh cultures after about five days, after that it starts to turn foul.

All you need to do then is make a fresh porridge mix, and place some of your old culture on to the top of your new porridge mix. If you use about three containers you will have a succession of cultures for continuous use.