In order to have an understanding of the nature of infestation, a total of 547 fish (54.7 % males and 45.3% females) collected from the two different environments were examined.

Infestation, the indicator of severity of attack has been described in relation to periods, size and sex of the host. A high percentage prevalence-(75.87%) was noticed owing to multiple infestation. Among the prevalence reported for different parasites, the infestation due to metacercariae was found to be more (33.52%) while it was less (13.92%) due to adult digeneans. Although no significant infestation was evident among sexes and biotopes, significant difference was noticed among parasitism (P=-0.01). The environmental influence on infestation and the possible causes for the increased or decreased infestation in host population have been elucidated. The results obtained have been statistically tested to find out the nature of dominance of infestation.