Common Metazoan Parasites of Fish
Parasites | Tissue | Susceptible Species | Signs | Diagnosis | Treatment | |
|---|---|---|---|---|---|---|
Myxozoans (intermediate host) | Myxosoma cerebralis (whirling disease) | Head, cartilage, backbone | Rainbow trout, salmonids | Blacktail, skeletal deformity | Histologic evaluation, isolation of parasite | None; regulatory concern |
Ceratomyxa shasta | Posterior intestine | Salmonids (Pacific Northwest) | Weight loss, distended and hemorrhagic vent | Wet mount, histologic evaluation | None; regulatory concern | |
Aurantiactinomyxon ictaluri (proliferative gill disease, hamburger gill disease) | Gill | Channel catfish | Mortality, piping | Wet mount, histologic evaluation | None | |
Henneguya | Gill | Channel catfish, other | None, severe hypoxia | Wet mount | None | |
Sphaerospora auratus (renal dropsy) | Kidney | Goldfish (pond-reared) | Mortality, severely enlarged and cystic kidney | Histologic evaluation | None | |
Tetracapsuloides bryosalmonae (proliferative kidney disease) | Kidney | Rainbow trout, all salmonids | Lethargy, darkening, fluid accumulation, exophthalmia | Wet mount, histologic evaluation | None | |
Monogeneans | Gyrodactylus (live bearer, except in Loricaridae) | Skin, fins | Goldfish, koi (predisposed) | Excess mucus, flashing, weight loss | Wet mount | Praziquantel in nonfood fish, formalin |
Family: Ancyrocephalidae Family: Dactylogyridae (egg layers) | Gills | Goldfish, koi, angelfish, discus, channel catfish | Piping, coughing, weight loss, skin lesions | Wet mount | Praziquantel in nonfood fish, formalin | |
Capsalids; Benedenia, Neobenedenia (egg layer) | Epithelium of skin and gills | Marine tropicals, other marine species, marine angelfish | Epithelial lesions, flashing, weight loss, mortality | Visual exam, wet mount | Praziquantel in nonfood fish, formalin | |
Polyopisthocotylea | Gill | Striped bass, hybrid striped bass, Florida pompano | Pale gills, piping, mortality | Visual exam, wet mount | Praziquantel in nonfood fish, formalin | |
Trematodes (intermediate host usually mollusc) | Heterophyidae | Gill | Redtail shark, black shark, rainbow shark, angelfish (freshwater), other pond-reared fish, aquarium fish | Flared gills, hypoxia, piping, do not tolerate shipping and handling | Wet mount | |
Clinostomum | Skeletal muscle | Largemouth bass, centrarchids, hybrid striped bass | Yellow grub | Direct visualization, wet mount | ||
Bolbophorus confusus | Skeletal muscle, viscera | Channel catfish | None | Direct visualization, wet mount | ||
Posthodiplostomum | Viscera, heart, posterior kidney | Largemouth bass, bluegill, centrachids, salmonids, other fish | None | Direct visualization, wet mount | None | |
Diplostomum | Eye (lens) | Fish are intermediate host (unspecified species) | Cataracts, blindness | Direct visualization, histologic evaluation | None | |
Cestodes | Diphyllobothrium latum | Viscera, musculature | Salmonids, other freshwater species | Adhesions, sterility (if gonads affected) | Direct visualization, wet mount | Praziquantel in nonfood fish |
Corallobothrium | Intestine (adult) | Channel catfish | None | Direct visualization, wet mount | Praziquantel in nonfood fish | |
Proteocephalus ambloplitis | Ovary (larval stage) | Largemouth bass | Sterility | Direct visualization, wet mount | Praziquantel in nonfood fish | |
Bothriocephalus acheilognathi | Intestine (adult) | Carp, aquarium fish | Weight loss, enteritis, mortality | Direct visualization | Praziquantel in nonfood fish | |
Acanthocephalids | Acanthocephalus | Intestine | Wild-caught freshwater fish, wild-caught marine fish | Enteritis, mortality | Direct visualization | |
Nematodes (fish as direct host) | Capillaria and Pseudocapillaria | Intestine | Angelfish, discus, zebrafish, tetras, barbs, and other aquarium fish | Weight loss, pot belly | Direct visualization, wet mount | Fenbendazole (25 mg/kg, PO, once a day for 3 days), levamisole, ivermectin (0.05 mg/kg, PO), emamectin (0.35 mg/kg, PO, once a day for 14 days) |
Camallanus | Posterior intestine | Largemouth bass, other centrarchids | Visualize worms protruding from anus | Direct visualization, wet mount | Fenbendazole, levamisole | |
Philometra | Posterior intestine | Aquarium fish | Visualize worms protruding from anus | Direct visualization | Fenbendazole, levamisole | |
Nematodes (fish as intermediate host) | Eustrongylides | Encysted in coelom | Angelfish, other aquarium species | Weight loss, pot belly | Direct visualization | |
Contracaecum | Encysted in viscera | Largemouth bass, centrarchids | Often none | Direct visualization | ||
Leeches | Leech | Skin | Freshwater game fish, aquarium fish | Anemia, weight loss | Direct visualization | None |