In an era where innumerable biological and synthetic compounds are perpetually introduced into the market every day in various forms, such as pharmaceuticals, cosmetics, nutraceuticals, fertilizers, pesticides, and nanoparticles, to serve multiple purposes, there is a need to develop rapid screening methods to evaluate their biosafety. Wide array of biomarkers used to demonstrate exposure to and effect of environmental contamination. In order to assess exposure to or effect of environmental pollutant on aquatic environment the following suite of fish biomarkers may be examined, oxidative stress parameters, hematological parameters, immunological parameters, genotoxic parameters and histology. The text explores the latest knowledge and thinking on these very important approaches for the assessment of environmental health, management and conservation. This review focuses on measurement of the genotoxic potential of chemicals in aquatic organism at different level of biological organization under field and laboratory conditions by using comet assay, micronucleus assay, polychromatic erythrocyte count.