Pathology of vitamin B‐6 deficiency in Channa (= Ophiocephalus ) punctatus Bloch

. Pyridoxine deficiency was experimentally produced in a population of Channa punctatus Bloch by feeding a pyridoxine deficient vitamin test diet for 240 days. The deficiency effects were further accentuated in another group of fish by adding 4‐deoxypyridoxine as an antagonist to the deficient diet. The behaviour, general morphology and growth of these fish were compared with control fish maintained on a complete vitamin test diet. The behavioural study revealed a series of nervous disorders such as ataxia, hyperirritability and muscular spasm followed by convulsions, fits, anorexia and paralysis in the posterior region during advanced stages of the deficiency. Gross morphological changes recorded were retarded growth and loss of weight resulting in a pinhead condition; integumentary damage such as scale loss, leakage of oedematous fluid and abnormal pigmentation, opacity of the lens resulting in complete blindness and enlargement and nodule formation in the spleen and kidney. Recovery treatment for 30 days comprising restoration of dietary supply of pyridoxine supplemented by intramuscular injections brought about considerable recovery in the fish with dietary pyridoxine deficiency but the antagonist‐treated deficient group showed little recovery, although further deterioration was halted.