Diversity and distribution of parasites from potentially cultured freshwater fish in Nakhon Si Thammarat

Twenty-one species from 16 genera of potentially cultured freshwater fish were examined for external and internal parasites. Ten individuals of each fish species were sampled from various places in Nakhon Si Thammarat. Eight groups, 72 species were identified and the majority was external (52 spp.). The parasites found were ciliated protozoan (2 spp.), myxozoan (2 spp.), monogenean (44 spp.), digenean (7 spp.), cestode (6 spp.), nematode (6 spp.), acanthocephalan (2 spp.) and crustacean (3 spp.). Monogenean was regarded as a major group of parasites with 44 species. Dactylogyrus (Monogenea) had the highest number of species (12 spp.), whereas Trichodina pediculus (Ciliophora) was the most widely distributed species observed from at least 7 fish species (7 families). Most of the parasites (72 %) found in this study were specific to their host species