Heavy metal poisoning means an excess of the required concentration that is found naturally on earth. In the present experiment, it has been observed that the natural water source surrounded by mountains is also polluted with arsenic because these heavy metals like arsenic are naturally contained in rocks that accumulate in the water source with soil erosion and rain. In this experiment arsenic was found in the water of Chhilpura pond, in which the haematology and biochemistry of catfish (Clarias batrachus) were studied, it was found that the RBC, haemoglobin, PCV, MCV, MCH, platelets, glucose and protein contents of catfish were found to be relatively low as compared to the control, whereas the WBC was observed to be higher to control and differential leucocyte count fluctuations were observed. It can be inferred from this experiment that heavy metals such as arsenic alter the haematology and biochemistry of catfish (Clarias batrachus).

In the present study, an attempt has been made to analyze the toxicity of fluoride and arsenic on morphology and behaviour of fish Clarias batrachus. Based on 96 hour LC50 values at the 95% confidence limits of sodium fluoride (NaF) and arsenic trioxide (As2O3) obtained from the preliminary tests, various sub-lethal concentrations of NaF and As2O3 were selected for combined toxicity testing. During the experiment, fish were regularly observed for any changes in their external morphology and behaviour. Behavioural changes were observed in terms of air gulping, opercular movement, swimming activity, body position, general activity and food sensitivity. Control fish remained normal throughout the experiment period (96 hour) but erratic, exodus and speedy movements were found in all treated groups. The number of air gulps (per 15 min, 24-96 hour) significantly increased (P<0.001) in the exposed Group I (20 mg.L-1 As2O3) as compared to control. A significant increase (P<0.01) in the number of opercular movements (per min for 24-96 hour) was recorded in treatment groups as compared to control. Apparent changes such as excessive mucous secretion, increased body discolouration, loosening of skin and complete loss of skin (head region and fins) were also observed. Skin loss was more intense in fish subjected to Group I.