Gastrointestinal Helminth Parasites of the fish Synodontis clarias (Siluriformes: Mochokidae) from Lekki lagoon, Lagos, Nigeria

A total of 362 specimens of the fish Synodontis clarias were randomly selected and subjected to parasitological examination for helminth parasites. They were collected over a period of one year from Lekki lagoon, Lagos, Nigeria. The prevalence of gastrointestinal infection was 38.7%. The helminth worms found include two cestodes, Proteocephalus spp., Wenyonia acuminata, and a nematode species, Raphidascaroides. Male specimens (196) presented a higher rate of infection (37.8%) than female specimens (166) which showed a rate of 23.5%. The overall worm burden was high (678) and it was independent of fish sex and fish size. Rev. In Nigeria the demand for fish exceeds supply and the proportion of animal protein in the diet is generally low. Parasitic diseases of fish seem to be one of the major problems con- fronting fish culturists. The Squeaker or upside- down catfish Synodontis clarias (Linnaeus, 1758) is a benthopelagic, potamodromous fresh water fish that inhabits water with a pH range of 6.5-9.5 (Reids 2004). The fish has been reported to present dioecism with external fer-