HATCHING / INCUBATION: HOW IT WORKS IN FISH FARMING: The fertilized eggs are spread on a screen usually mosquito net of size (1mm), which is placed in the incubator. The hatched eggs will pass through the screen while the dead eggs and shells remain on the screen.
Thus in case of no aerator, which is used to generate oxygen in the system, the use of gentle flow of water with uniform pressure in both the inlet and outlet pipe is ideal or adopted. This help to introduce oxygen to the water and also maintain water quality.
Incubator tank depends on the hatchery design and can be made of various material, plastic basin or tank with a flow-through water system.
HATCHING AND FRY MANAGEMENT
Hatching starts in the incubator within 24hours depending on the temperature. After 36hours of hatching, remove the substrate or kakabans or tray used for spreading the eggs. This should be kept in a separate tank or bowl with clean water as more hatching may be attached. Treat and sundry the substrate for next breeding exercise. Carefully siphon out dead and spoilt eggs out of the incubation tank. The hatchlings posses yolk sac which serves as food for the first 3-4 days. After this stage start feeding them with artemia, alternatively, you can feed with half cooked egg or high quality fish meal.
After 7-10 days you can add formulated feed with or without artemia, which will help them grow into fingerlings. To obtain quality fry start feeding at right time. When they are about 7-10 days old, it is advisable to transfer the fry into a bigger nursery tank or pond where they will grow into fingerlings that is separate them out.
Generally; you start observing fry differential growth, start sorting after 1-2 weeks to remove shooters.
The nursery pond is usually small in size and is used in culturing fingerlings. It has square or rectangular shape. In Integrated Agricultural Training Center, they have six sub compartment locations in two roots. The pond can contain up to 2000 fingerlings fish at a time.