In the present studies, all the three metallic compounds viz. Hg(II), As(III) and Cu(II) registered a significant decrease in MI vis-a-vis negative control (group I) even against sublethal exposures or shortest exposure period of 24 h. Moreover, even lesser RMI than positive control (group II) coupled with elevated frequencies of CA for above said compounds form a valid ground for potentially cytotoxic nature of these metallic compounds. Further,a reduction of RMI values is indicative of delay of interphasic stage of cell cycle on account of activation of DNA damage and repair processes. This is evident by increasing frequency of chromosomal damage within the subsequent time interval. These genotoxic anomalies increased gradually up to 72 h, after which they registered a declining trend. Similar observations were documented by Yadav and Trivedi [51] in C. punctata following exposer to sublethal concentration of chromium (VI) up to 168 h. In another study, De Lemos et al.[58] accounted significant induction of micronucleus in fish erythrocytes exposed to chromium (VI) for 21 days but with a decrease thereafter. Brunetti et al.[59] reported that the higher concentration of toxicant might inhibit normal cell division, damage chromosome and interdict DNA duplication, thus cytotoxic damage more or less declined.