A biometric study of growth of various body parameters in relation to standard body length, length- weight relationship, relative condition factor and fecundity of the mud eel (Mastacembelus armatus) has been made. The fastest growing body parameters is the region between the snout and ventral fin. This is followed in decreasing order by snout to dorsal fin, pectoral fin to anus, breadth at the dorsal fin, snout to pectoral fin and head length. The length-weight relationship follows the cube law during summer months. The male and female fish become sexually mature when they attain a length of 15.5cm (just above 15gand nearly 18cm (22g) respectively. The fecundity of this species is very low (210-1828). The advantges and disadvantages of the form aquired by M.armatus in response to selection pressure are discussed. The peculiar shape, growth pattern of body paramters and low fecundity render this fish totally unsuitable for commercial exploitation.