A Study on Reproductive Behavior and Fry Nursing of Koi Carp (Cyprinus Rubrofuscus) in Sunsari, Nepal

A study was conducted emphasizing, the induced breeding techniques, breeding behavior and nursery rearing of koi carp at Everest Aquaponics and fish farm, Sunsari, Nepal. The study was done in the hatchery Unit of EAFF for 36 days including 28 days of fry nursing from 15 May to 26 June. Ten set of brooders in the ratio of 1:2 was used. The average body weight of the female brooders was 910±164.722 gm and a female weighing one kilogram gives approximate 70,219.78 eggs in induce breeding method by hand stripping. The percentage of average fertilization rate was 68.6±3.58 %, the average hatching rate was 75.75 ± 5.9% and average survival of spawn was 66.88±5.84%. The size of the fry after hatching also varied between 2.3-3 mm whereas the fry growth varied from 17- 24mm and the average survivability from fry to fingerling was 88.9±1.59%. The mean final weight of the fry in the nursery tank was 1.0845±0.0353 gm and the average weight gain after 28 days of nursery rearing was 0.9315gm±0.013298gm. The average of the water quality values including temperature was 27.5°C, pH was 7.975, dissolved oxygen was 6.55 mg/L, NO3 concentration was 3.75 mg/L during nursery raising whereas the average water parameters during breeding were 26.75°C, pH of 7.995, DO of 6.25 mg/L, NO3 of 4.375. Successful koi farming can reduce the uncertainty and unavailability of fingerlings, can increase large-scale production for export, and can be a potential area to meet national needs and help increase revenue in foreign currencies. Current research will certainly pave the way for startups to launch commercial production and commercialization of Koi carp in the coming days