Frozen Food
Frozen food can usually be fed approximately 14 to 21 days post hatching. Instead of hatching fresh brine shrimp nauplii for your baby and juvenile rainbowfishes every day, you might consider making frozen brine shrimp blocks and feeding these instead. First, hatch a large batch of brine shrimp. After hatching, collect the shrimp in the normal way and rinse with fresh water. Place the normal ration of brine shrimp for a tank into the well of an ice cube tray (plastic ones that make small cubes are best). Add fresh conditioned water to fill the trays and freeze. When it is time to feed the fish, just pop out a block and add to the tank. The ice will slowly melt and release the brine shrimp, feeding your fish. You can do the same thing with other types of live food.
A suitable homemade food can be made up with fish, shrimp, and/or squid flesh, chicken eggs, beef liver, and cod liver oil. The fry should be eating brine shrimp nauplii before feeding this food.
Percent weight: Fish, Shrimp, etc. – 85% Cod Liver Oil – 2% Chicken Eggs – 10% Beef Liver – 3% The recommended procedure for preparation is as follows: Thaw shrimp, squid or fish (if frozen) and blanch the liver in boiling water for at least 10 minutes. Homogenise with fish, shrimp, or squid in a food processor until well blended (smooth texture with no chunks). Mix chicken eggs, cod liver oil, and then add to food processor. Add a binding ingredient (gelatine or agar) gradually, and continue mixing slowly until a paste is formed. Take the paste and place in a plastic ice cube trays and store frozen. Later, the frozen food can be finely grated with a cheese grater.
This procedure will result in a mixture of particle sizes ranging from 250 to 1,000 µm. However, depending on the size of the fish, you may require a certain particle size. To obtain the specific particle size, take a frozen cube out of the freezer, thaw and blend with water in an electric blender and manually press the material through a sieve having a specified size. Drain the sieved diet to remove dissolved particles that can foul the water and contribute to bacterial growth within the nursery tank.
