Abundance and distribution of the endoparasitic helminths in Anabas testudineus (collected from a polluted water body) was analyzed. Out of 50 fish observed, 42 (84%) were parasitized by at least one species. Five metazoan endoparasites, one trematode (Neopecoelina saharanpuriensis) and four nematodes (Ascaridida sp., Contracaecum sp., Camallanus anabantis and C. pearsei) were recorded. Prevalence was higher in female (90%) hosts than males (75%). A significant positive correlation was observed between the standard length of the host and the abundance for parasites except Ascaridida sp.Nematodes were the more prevalent group (72%) than trematodes (48%). No parasitic species was observed as central species category; three parasites (N.saharanpuriensis, Ascaridida sp. and Contracaecum sp.) were considered as secondary and Camallanus spp. as satellite species. All nematode parasites showed aggregated distribution pattern and the trematode showed random distribution pattern. Interspecies association between two species of parasite was low.

Community structure of metazoan endoparasites of Anabas testudineus collected from an unpolluted and a polluted water body was determined. Out of 100 A. testudineus observed, 78% was parasitized by at least one species of endohelminth parasite. Eight metazoan endoparasites were recorded. Nematode showed higher prevalence than trematode. One species was accounted as satellite species and others as secondary. Larger hosts were more abundantly infected than the smaller ones as positive correlation was observed between the standard length of the hosts and the abundance/ prevalence of all parasites. Maximum parasite species followed a typical overdispersed type of distribution pattern. Parasite species richness was lower in fish from polluted (4) than unpolluted water (6). Per cent similarity of infestation between the sample hosts was high (55.73%). Three common parasite species from both sample hosts showed insignificant difference in intensity of infestation in relation to host habitat. Host sex had influenced infestation at infra-community but not at component community level. Interspecies association between parasites was strong in fish from unpolluted in comparision from polluted water. Host's habitat quality also played an influential role in building parasite community, diversity and other associated community indices.

Community structure of the parasites of Anabas testudineus was analyzed collected from a fresh water body, Turag River at Diabari, Mirpur point of Dhaka, Bangladesh. Out of 50 A. testudineus fish observed, 36 (72%) were parasitized by at least one species of helminth endoparasites. Six metazoan endoparasites were recorded: two trematodes (Allocreadium minutum, Neopecoelina saharanpuriensis) and four nematodes (Ascaridida sp., Gnathostoma spinigerum, Contracaecum sp., Paragendria wallagonia). Prevalence was higher in female (81.25%) hosts than male (55.56%). Nematode was more prevalent group (70%) than trematode (62%). All parasite species were accounted as secondary species category; no central or satellite species accounted in the sample. A significant positive correlation was observed between the standard length of the host with the prevalence and abundance of all parasites in this sample fishes. Two parasites (A. minutum and Ascaridida sp.) showed typical over-dispersed distribution pattern and other four parasites (N. saharanpuriensis, G. spinigerum, Contracaecum sp. and P. wallagonia) showed random distribution pattern. Interspecies association between two species of parasite was moderately strong. The host’s sex did not affect the parasite diversity and abundance.J. Asiat. Soc. Bangladesh, Sci. 40(1): 67-77, June 2014