Captive Breeding of Some Endemic Ornamental Fish Species in Sri Lanka
H.M.P. KITHSlRI, P.P.G.S.N. SlRIWARDENA AND GR. HEMALEE RUPIKA
There is a high export demand for some endemic fish species in the ornamental fish trade in Sri Lanka. Many endemic ornamental fish species are reported to be in decline and some have become endangered due to a combination of several factors including overexploitation, aquatic pollution, and habitat modifications. Some of the endemic fish species in Sri Lanka are listed as either restricted or prohibited species for export. Present study reports preliminary results of a series of investigations on the factors affecting the breeding and fry rearing of some high demanded endemic fish species in captivity for the purpose of domestication of a broodstock.
Eight endemic fish species namely Malpulutta kretseri, Belontia signata, Danio pathirana, Rasbora vaterifloris, Puntius cumingii, Puntius srilankensis, Puntius titteya and Puntius nigrofasciatus were used for the present study. Fish were kept in 150 cm x 90 cm x 75 cm cement tanks with water to a depth of 60 cm and provided a breeding environment using aquatic plants and pebbles. Tank environment was monitored daily for water temperature, pH and dissolved oxygen content, weekly for unionized ammonia, nitrite and fortnightly for alkalinity and hardness. All the fish were fed with live feed such as Moina, mosquito larvae and microworms and pelleted feed.
Though the most of the endemic fish live in waters with a pH ranging from 5 to 7, and hardness and alkalinity ranging from 40 mg l-1 to 120 mg l-1, it was found that all eight species used in the present study could be bred in captivity in waters with pH ranging from 7.5 to 9, alkalinity ranging from 26 mg l-1 to 67.2 mg l-1 and hardness ranging from 36.8 mg l-1 to 66.4 mg l-1. Survival rates of fish fry were 75%- 92% for all fish species except in Malpulutta kretseri, which had a survival rate of 41%.