Summary study of gill ectoparasite infections and their histopathologic effects in four species of freshwater ornamental fishes

Ornamental fish are more expensive in comparison with the other fish. It especially highlights in non-breeding fish (in imported one for importation costs). But of course, with entering the new and unhealthy fishes to aquarium or ponds, they may transmit a pathogen to others (interfere with Iran ornamental fish parasitic fauna). In this study (Dec. 2008- Sep. 2009), 400 fish gill arch from 4 species of ornamental fish (within focus on imported fish); namely, i.e. Goldfish (Carassius auratus), platyfish (Xiphophorus maculatus), Dwarf gourami (Colisa lalia) and Catfish (Hypostomus plecostomus) were inspected for gill ectoparasites and then pathologic effects (but in high- affected gill). In this study, seven protozoan and ten metazoan species, indeed seventeen parasite species were identified. Protozan parasites consist of: Trichodina spp. and Ichthyophthirius multifiliis were found in four fish species; Ichthyobodo necatrix (Costia necator/C. necatrix) and Cryptobia branchialis, were respectively found in Dwarf gourami and goldfish. The highest prevalence belongs to Ichthyophthirius (47%) in platyfish. Metazoan parasites consist of: Ancyrocephalus sp. (Dwarf gourami), Ancylodiscoides spp. (catfish and platyfish), Dactylogyrus vastator, D. baueri, D. formosus (only in goldfish) and Gyrodactylus spp. (in four fish species). The highest prevalence was related to Dactylogyrus vastator(82%) in goldfish. Histological effects in case with high prevalence of parasite were also observed, e.g., hypertrophy, Lamellar hyperplasia and fusion. In high-parasitized gill, there is dysfunction of gill.