FAMILY: Pangasiidae
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NAME: Pangasius sp. - Tricolor shark, Rainbow shark, Iridescent shark |
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Data provided courtesy of Aquaculture/Fisheries Center, University of Arkansas at Pine Bluff - (Dr. Peter Perschbacher) |
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DISTRIBUTION:
This genera of large catfish is found native to Asia including Thailand, China and Cambodia in rivers such as the Chao-phy and the Kreang Kri Cannal. They are freshwater fish broadly distributed between Pakistan and Borneo. HABITS: The iridescent shark, so called because of its mid-water swimming style and similarity in terms of shape to its namesake, isn't, however, an aggressive fish in home aquariua. It is very, very nervous. This skittishness is further compounded if kept alone or in an unsuitably small aquarium. They are usually carnivorous during the juvenile stage, but become more omnivorous as they mature. Pangasiids are large catfishes with most species attaining at least 50 cm or more. Many are also schooling. The fish stays in the deepest parts of the largest rivers and thus is rarely caught in the wet season. They may become solitary and very territorial at large sizes. They are reputed to have a fondness for dogs whose floating carcasses are common in the rivers during the wet season. SPAWNING: Natural spawning occurs in rivers during the month of June. In captivity both males and females receive hormone boosters of Clarius and Pangasius sutchi pituitary extract and are dry spawned. This method involves stripping the eggs and milt form the female and male, respectively, into a bowl and mixing them in the absence of water. Eggs are then placed in fine mesh hatching nets containing aquatic plants or palm and jute fronds. The fry emerge 24-30 hours post-fertilization at 30C and are immediately placed in clear water. GROWTH: Species of Pangasius are behemoth freshwater fishes. Records indicate that fish measuring 3 m had been caught in river systems, but P. sanitwongsei of this size have not been seen since the early 1920's A 3 meter long fish would be a meter thick! In 1925 a 2.5 meter fish was caught in a cast net above Raheng, Thailand. Fish may obtain a weight of 4kg in 2 years in many culture ponds. USES: The catfish of this family are the primary source of fish flesh in small Asian communities that don’t actively raise carp. This is a food fish and is commonly taken with seines, gill-nets, or hook and line then marketed fresh. Prior to 1997 this fish was rare in the aquarium trade. Those that made it into the trade were usually by-catch of South East Asian shipments. This fish is now farmed in ponds for food and those specimens appearing in the aquarium trade come from fish spawned for aquaculture. CULTURE: Pangasiids are raised in many countries across Asia and therefor many culture methods employed. In Thailand, Cambodia, and Vietnam they are commonly raised in cages placed in ponds. They are fed kitchen waste, bananas, rice bran, cooked broken rice, and soft aquatic plants. They are used as a component of pig-poultry-fish farming in Malaysia. In this case ponds are fertilized with poultry and pig dung, but production and growth rates are very low in this system. Farmers must sort and cull at very short intervals to ensure survival rates. Farmers often make their own feeds. A common feed is made by mixing locally available vegetable, rice bran , chicken intestines , fish meals etc and then cook the mixture. Vitamins such as vitamin C and other feed ingredients are added after the feed has cooled down. They are also commercially manufactured pellets available in Malaysia. REFERENCES:
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