6b514bce_ter_Fish___Minnesota_Sea_Grant__Symptom
[Parasite] Glochidia (larval stage of many freshwater mussels) [Type] mussel [Description] Soon after attaching, become encysted; appear as enlargements. Cysts open, mussels fall to substrate, develop into nonparasitic adults. [Edible] Yes [Recommendation] Clean fish and prepare as usual [Symptom] 
Tiny freshwater mussels attached to gill filaments or fins. May also appear as lumps on gill filaments or fins
Parasites of Freshwater Fish | Minnesota Sea Grant
Symptom