Cystobranchus
Cystobranchus is a genus of leeches belonging to the family Piscicolidae. These leeches are associated with freshwater fishes and closely related to the genus Piscicola. They are distributed in Europe and North America. They attach themselves on the external part of fish and feed on their blood, which could cause the fish to be more susceptible to stressors and diseases.
Species in this genus include:Cystobranchus fasciatus Cystobranchus meyeri Hayunga & Grey, 1976Cystobranchus mammillatus Cystobranchus moorei Cystobranchus pawlowskii Sket, 1968Cystobranchus salmostiticus Meyer, 1940Cystobranchus verrilli Meyer, 1940Cystobranchus virginicus Hoffman, 1964Cystobranchus vividus Verrill, 1872