Water fleas constitute major zooplankton population of fresh water aquatic ecosystem. Their population density is an indicative of well-being of aquatic bodies. Simocephalus vetulus (Crustacea - Cladocera) is a tailless water flea and is well suited lab model for environmental monitoring. Copper a Gray listed heavy metals despite being an essential micronutrient, becomes highly toxic when present in excess quantity in aquatic ecosystem thereby causing deleterious effects on aquatic flora as well as fauna. The water-flea exposed to acute 0.37 mg/l (96hr LC50), sub-acute 0.0925 mg/l (25% of 96hr LC50) value and chronic 0.037 mg/l (10% of 96hr LC50) value of copper sulphate and acute 0.16 mg/l (96 hr LC50), sub-acute 0.04 mg/l (25% of 96 hr LC50) value and chronic 0.016 mg/l (10% of 96 hr LC50) value of potassium chromate showed behavioural alterations like initial hyperactivity, fast appendage movements and in phototaxis, geotaxis and avoidance indices. At later stage erratic swimming and spinning, reduced activity, loss of balance, reduced feeding and darkening of cuticular coloration, reduced phototactic, geotaxis and avoidance indices were the major effects on its behaviour. The behavioural alterations of S. vetulus showed the most susceptible and foremost indication of potential toxic effects. Various behavioural parameters, used in present study may serve as better biomarkers about metal toxicity and monitoring of drinking water quality
Acute toxicity of copper sulphate and potassium chromate to “tailless freshwater flea”, Simocephalus vetulus (Crustacea-Cladocera).