Qualities of A Healthy Fish Stock and Good Stocking Practices

a. Fish stock should be of known source (Dutch variety, etc) and be part of a breeding programme for continuous stock improvement; be sure fish fingerlings are not from unknown wild stocks of questionable species caught by fishermen. Fish fingerlings should be certified disease free. Farms should have tanks or ponds to quarantine fish initially to confirm the quality of their health. b. Fish for stocking in production ponds should be at least 10 cm in total length and preferably up to 15 cm in size. This will greatly reduce mortalities and ensure high survival of stocked fish. Fish of this size are very hardy and resistant to handling and transport. c. Fish fingerlings should come from a certified fish hatchery with procedures for conditioning fish (2 days without feed) for transport in tanks and/or plastic bags. Fingerlings should have been graded to have similar size fish. Certified hatchery should have standardized procedures for grading and handling fish and preparing them for transport. d. Fish for stocking should be in good condition without sores or injuries on their skin; uniform skin color is another indicator of good health. Fish should be acclimatized slowly to the pond environment. Fish should have good overall appearance and be lively. e. With catfish, stock the pond assuming a carrying capacity of 10-15 tons/ha, which will call for a stocking density of 2 fish/m2 assuming a mortality of 10% using 15 g fish fingerlings for stocking. Assume a harvest size of at least 800 g per fish. f. With tilapias, stock the pond assuming a carrying capacity of 5-8 tons/ha with use of quality fish feeds. Calculate stocking rate based on a harvest weight of 400-500 g/fish. Stocking should be done with monosex male tilapias as they grow twice as fast as females. Fish can be sexed visually by hand or sex reversed tilapias can be used. Mixed sex mono species cultures of tilapias will lead to stunted fish and over population. Catfish can be stocked at 1 catfish for each 10 tilapia to control reproduction. Catfish can be stocked up to 2 months after the tilapia are stocked. g. records should be kept regarding all fish stocks and growth.