Ornamental fishes are really nature's wonderful creation. Ornamental fish keeping is the second most preferred hobby in the world. Koi is one of the most popular decorative fish in many countries all over the world, including the United States. It belongs to the family cyprinidae and originated from mountainous Yamakoshi region from Japan. The present study was conducted in duplicate, the mature brooders (250-300 gm) were induced with synthetic hormone WOVA-FH at 3 different doses (0.3, 0.5 and 0.7 ml/kg) and control (without hormone inducement) to standardize the ideal dose for induced breeding. Healthy brooders were collected from nearby ornamental fish market kolathur, Chennai. Collected fishes were acclimatized to captive condition. The brood stock was successfully conditioned in RAS facilitated FRP (1ton capacity) tanks with a nutritionally balanced fish diet (38% protein) and intermittently fed with Tubifex worms for a period of one months. Induced breeding was achieved using all three doses but significant difference was observed at different doses.
At 0.5 ml/kg WOVA-FH showed better performance with highest fecundity of about (15466±338.29 nos/female) and the hatching rate (82±1.2%) comparatively. The study concluded that WOVA-FH is an ideal hormone for induced breeding of koi carp at a dosage level of 0.5ml/kg based on the results obtained. Fertilised eggs (1.38-1.41mm) were in milky white to yellow colour attached to the substrate present in the tank. Yolk sac remained up to 72 hrs of post hatching and the yolk sac length of about 2.86mm. Complete developmental sequence from egg to hatchling stage of koi carp was recorded for the fishes bred by hormone induction. The hatchlings are fed with live feed according to the mouth size 1st week(1.26mm) with rotifer,2nd week with cladocerans followed by formulated feed.