Haematological response of fish Channa punctatus (Bloch) to chronic zinc exposure.

Sub-lethal concentrations of zinc administered to freshwater teleost, Channa punctatus for a period of 135 days brought about significant haematological alterations. The RBC count, haemoglobin and haematocrit content progressively decreased while WBC count, MCV, MCH and MCHC increased. Alterations in the haematological parameters were dose and duration dependent and can thus serve as a useful physiological index.