Haematological effects of nickel toxicity on a fresh water teleost, Colisa fasciatus.

Colisa fasciatus, a freshwater teleost, were exposed for 90 hrs to 45 p.p.m. nickel sulphate under static test conditions. The treatment resulted in leucopenia due to reduction in the number of small lymphocytes and polycythemia with concomitant increases in the haematocrit and haemoglobin values, and in retardation of the erythrocyte sedimentation rate of the moribund fish. No differences in total thrombocyte count, clotting time, and hepatosomatic index were found between the control and the treated fish. Lymphopenia and erythrocytosis may be used in presumptive monitoring nickel toxicity in fish.