VPP 322: Aquatic Animal Diseases, Health Care and Management (1+1)

GOLD FISH

• Generally the gold fish attains sexual maturity in a period of five months at 27- 30 ºC and under good nourishment. Staple live diets such as earthworm, daphnids, blood worm, tubifecids, squid meal, and clam and oyster meat are preferred by the fish. The sex of berried female may be identified by the swollen belly, which denotes the presence of matured ova. Matured males on the other hand are identified by the presence of tubercles immediately after spawning.
• For the purpose of breeding, females and males are introduced in the spawning tank of 40 - 100 litre capacity at 1:2. Mass breeding is also possible in a large, circular cement tank (3 m dia and 75 cm high) containing aerated water and aquatic weeds such as Certaphyllum demersum or Hydrilla sp, or synthetic nylon fibrils in bunches. The water in the breeding tank should have temperature of 20- 27º C , pH 7-7.5. About 500 sticky eggs are released per spawning which is normally held in the morning. The eggs measure 1 mm in dia. The incubation period is 65-72 hours at 25-31ºC.
• The hatchlings do not feed until the fifth day as they depend largely on endogenous nutrition i.e yolk. From the sixth day onwards, they are fed with infusorians. The emerged fry are fed with Artemia nauplii or Cyclops for about 10 days, thrice a day. The young fish are then fed with tubifecids or Chironomous larvae in addition to artificial diets. The weeds containing the adhesive eggs are finally removed to another tank. Alternatively the parents could be removed to the stocking pond leaving the eggs in the spawning tank.