Biology of great white sheat fish (Wallago attu) and one-spot glass catfish (Ompok bimaculatus) family siluridae in southern provinces

Great white sheat Fish (Wallago attu) and One spot Glass Catfish (Ompok bimaculatus) are belong to 2 genus: Wallago and Ompok , Family Siluridae, Order Siluriformes. They distributed from India to Indonesia, living in rivers and streams. They are among high value, freshwater fish species naturally distributed in river system of South Vietnam. They usually live at upper and middle of river and stream. The intestine to standard length ratio is smaller than 1. They are predator fish, main feed is fish. Characteristics of Great white sheat : Barbels two pairs; maxillary barbels extending to 1 / 3 of anal fin. Eyes small, with a free orbital margin. Mouth extending beyond eye. Dorsal fin small; anal fin very long. Maximum length 200 cm. The Gonado-Somatic Index (GSI) is 4.47 percent (4th Stage). Breeding season from May to July. One - spot Glass Catfish: Barbels two pairs; maxillary barbels reaching pelvic fins or anal fin. Eyes small, covered by skin. Dorsal and pelvic fins small; anal fin long. A round spot on side above pectoral fin. Maximum length 50 cm. GSI is 9.96 percent (4th Stage). Fish can breed during the year but concentrate in August and September