Of the total 240 Pangasius hypothalamus (5 - 8.7cm) fry examined during September' O1
to February'02, 80 (33.33%) were found to be infested with one or more ecroparasites
irrespective of genera or groups. Seven parasitic groups were identified with the highest
average prevalence of Trichodinids (55%) followed by Dacrylogyrus spp. ( 42%), Episrylis
spp. (8%), Apiosoma spp. (7%) Argulus spp. (5%), Gyrodacrylus spp. (4%) and Piscicola
spp. (2%) the lowest prevalent group irrespective of months. Trichodinid and
Dacrylogyms spp. were recorded to be the dominating parasitic groups among the seven
both in terms of monthly prevalence and severity of infestation throughout the period of
investigation. The highest prevalence (60%) of ectoparasite was recorded in December
and the lowest (10%) in February irrespective of groups
