6b514bce_ter_Fish___Minnesota_Sea_Grant__Symptom
[Parasite] LEECHES [Type] leech [Description] Conspicuous blood-feeder; produce small circular wound that persist though leech may drop off. Up to 1½-inches long. [Edible] Yes [Recommendation] Clean fish and prepare as usual [Symptom] 
Flattened, segmented worms attached to body, gills, fins, or mouth; sucker on both ends. Can be greenish to black; undulating
Parasites of Freshwater Fish | Minnesota Sea Grant
Symptom