Health variables and gill morphology in the tropical fish Astyanax fasciatus from a sewage-contaminated river.

The relative condition factor (Kn), gonadosomatic index (GSI), selected hematological variables and gill morphology of the fish Astyanax fasciatus were analyzed in two sites (site 1 was unpolluted and site 2 was polluted with untreated domestic sewage) of a tropical river (Camanducaia river, Sao Paulo State, Brazil). The relationship between the body mass (M(B)) and the standard length (L(S)) of A. fasciatus from both sites was M(B)=0.