If one does the literature research, just about every wild fish, esp river fish is infected by some form of the documented parasites for each species.
Examples:
BG - protozoans 9, Trematoda 56, Cestoda 8, nematodes 11, acanthocephalans 5, leeches 6, mollusks 1, crustaceans 12.
GSF - protozoans 4,Trematoda 29, Cesstoda 5, Nematoda 7, Acanthocephala 2, leeches 1, Mollusca 1, Crustacea 4.
LMB - Protozoa 13, Trematoda 45, Cestoda 11, Nematoda 14, Acanthocephala 5, leches 4, Mollusca 1, Crustacea 10.
Reference: Parasites of North American Freshwater fishes. 2nd edition. Cornell Univ. Press 539pp. G.L Hoffman 1999.
https://academic.oup.com/jaah/article-abstract/11/2/198/7826351
