The aim of the present study deals with the effect of Physico-chemical variables on mercuric chloride induced toxicity on Labeo rohita. In mercuric chloride induced toxicity studies, essential physico-chemical variables like ammonia nitrogen, DO and TH contents were also determined; results showed a significant diverge dissimilarities in diverse mercuric chloride status on Labeo rohita. Sampling, experiment and finding were calculated in triplicate. In 0.15 (mg/L) mercuric chloride status, maximum TH 9.15±0.16 (mg/L) were found, similarly maximum DO, 9.18±0.22 (mg/L) were recorded with 0.54 mercuric chloride level. Another eliminating ammonia nitrogen (mg/L) parameter shown maximum 0.58±0.31 (mg/L) values with reference to 0.24 (mg/L) mercuric concentrations.