Finfish Breeding and Hatchery Management

Hatching of eggs
● Transfer the developing eggs which are attached to the plants/fibres  to hatching hapa or circular tank for hatching where running water is maintained.
● The eggs are adhesive, small (1-2 mm diameter), with narrow perivitelline space, spherical and pale-yellow (fertilized); unfertilized eggs are opaque white
● The stocking density of eggs is 50,000 - 1,00,000 eggs per hapa (2 x 1 x 1 m) or 25-30 lakh eggs per circular hatching tank (4-5 mm diameter.
● The eggs hatch in 36 – 72 hours at 26 – 31⁰C.
● Hatching is very effective in Chinese type of circular tank
● The newly-hatched spawn is heavy (remain attached to hapa wall), 4-5.6 mm long, with prominent eyes.
● Allow the yolk-sac spawn to remain in the hapa or tank till it becomes free-swimming.