PREPARATION OF ORNAMENTAL FISH FEED

Preparation of dry feed using two ingredients Using rice bran (protein 9%) and ground nut oil cake (protein 45%) a fish diet with 27% protein can be prepared as follows. A square is constructed and the two ingredients are put on the two left corners along with the protein content of each. The desired protein level of the feed is placed in the middle of the square. Next, the protein level of the feed is subtracted from that of the ingredients and the answer is placed in the opposite corner.

Square method

Square method – Contd… Now the figures on the right side corner of the square are added i.e.18+18=36 Then the % of rice bran to be added in the feed = x 100 = 50% % of Groundnut Oil cake = x 100 = 50% 36 To make 1 kg feed 500g rice bran and 500g-groundnut oil cake should be added.

Flow chart - Preparation of dry feed Feed ingredients ↓ Sieved through 300 micron mesh ↓ Mixing ↓ Addition of water 30 – 35% ↓ Dough ↓ Cooking for 15 min in pressure cooker ↓ Cooled ↓ Oil + Vitamin + Antioxidant + growth promotion + Antibiotic + colouring agent sprayed over the feed. ↓ Remixing ↓ Pressed through hand pelletiser (2mm) ↓ Drying

Dry feeds

Culture of live food organisms Infusoria Materials used for culturing infusorians include hay, banana peels, dried beans, lettuce, cabbage, egg yolk, malted milk, skimmed milk (dried), hay seed, dried blood, spinach, dried aquatic plants, etc. A medium may be prepared by first boiling any one of the above ingredients, It is then diluted with freshwater, kept in a plastic trough or cement tank of 50 to 100 lit. capacity.

Culture of live food organisms – Contd… Infusoria The fertilized water medium may be covered with velon screen for bacterial development, fermentation and subsequent leaching of nutrients. Within four days, the water turns greenish, which indicates the production of infusorians. A mild aeration and alkaline pH may enhance the production of the infusorians.

Culture of live food organisms – Contd… Rotifers The common freshwater rotifers are suitable for feeding a variety of ornamental fishes. The mass culture of these rotifers could be undertaken in plastic troughs or circular tanks of 250 l capacity. A mixture of poultry droppings, groundnut oilcake and triple super phosphate is prepared at 150ppm, 20ppm and 20ppm respectively and are added to the tanks containing water.

Culture of live food organisms – Contd… Rotifers The medium is then inoculated with Brachionus sp. on the third day at the rate of animals per ml. The above liquid manure may also be added in alternate days when the density reaches 1 ml organisms/m 3. A bolting silk and plankton net of 50mm mesh size could be used to sieve out the organisms for feeding the fishes. The harvested rotifers should be washed in freshwater before their use in feeding the fish fry.

Culture of live food organisms – Contd… Blood worm (Chironomus larva) Blood worm (Chironomus larva) The intermediate stage of the midge fly is commonly called as bloodworms. These worms are ideal live food source to all varieties of ornamental fishes. The chironomid fly normally lays about 2000 eggs at a time in any substratum of the stagnant water and such eggs hatch out in the presence of sunlight in a period of about three days. The larvae attain the optimum size in about days, when they are ready for feeding fishes. These worms could be disturbing the mud bottom.

Culture of live food organisms – Contd… Blood worm (Chironomus larva) Blood worm (Chironomus larva) The larvae of chironomus feed on phytoplankton like Nitzschia sp., Navicula sp, Chlorella sp, Chlamydomonas sp. etc. Hence any organic manure, which helps in the generation of these algae, may be used for fertilizing the pond to facilitate the adult fly to lay the eggs. Organic manures like cow dung, pigdung, poultry waste either alone or in combination with groundnut oilcake and super phosphate may also be used to enhance the production of algae and flagellates.

Culture of live food organisms – Contd… Blood worm (Chironomus larva) Blood worm (Chironomus larva) Tanks of any size may be used in the production of Chironomus larvae. Larvae collected from the wild should be washed and treated with suitable dose of antibiotics in order to prevent bacterial or pathogenic infection.

Culture of live food organisms – Contd… Tubifecid Tubifecid The tubifecid worms are annelids, which normally dwell inside tubular cases. They are common in sludge banks or silty shores of aquatic areas rich in nutrients. As they are available throughout the year, the supply is not restricted. As Tubifex contains n3 and n6 fatty acids, it is an ideal live food source especially for brood fishes such as goldfish, angel and ocsar.

Culture of live food organisms – Contd… Tubifecid Tubifecid Tubifex could also be cultured in race ways fertilized with organic manures. For harvesting tubifecid worms from the wild habitats i.e, soil, the latter is first dried. During drying, the animals would lump together and form balls. These balls should be washed in running water to remove the gut contents before feeding them to fishes.

Live food organisms