So what are these parasites on a walleye

[Gil Levesque]

Caught this walleye today on lake erie. Part of a nice limit of six! It had these things on all its fins! Looked to me like maybe lamprey larvae! Any guesses?

[Gil Levesque]

They were attached by a ...sucker like a leech and there was blood around the area!!

[wkrp]

Trump Lumps. No question about it.

[kickingfrog]

Definitely not anything lamprey related.

[sauce]

Leeches.

[akaShag]

They look like leeches to me, but I have never seen them on a fish.

[phishfearme]

see the following thread and link to wiki:

https://www.walleyecentral.com/forums/showthread.php?t=630418

https://en.wikipedia.org/wiki/Rhynchobdellida

[dave524]

Surprised to see them on a open water Erie fish, I would have thought you would more likely encounter them on say a resident Grand River fish or some other soft bottom. weedy, warm body of water.

[sauce]

7 hours ago, dave524 said:

Surprised to see them on a open water Erie fish, I would have thought you would more likely encounter them on say a resident Grand River fish or some other soft bottom. weedy, warm body of water.

My observations show that it's actually the opposite in southwestern Ontario. I catch walleye with leeches on them at the end of the season in March. I have never caught a walleye with a leech on it in the summer. I've found leeches on my waders after trout fishing in April. Never happened in the summer on the same river. There's a certain trout stream I won't fish without waders. The strain of leeches there find you fast.  Leeches like cold water. I'm pretty sure they seek it out, along with blood!

I think the OP's fish came from deep water way below the thermocline. Probably very close to bottom.  And probably not very far from a depth change and some significant weed growth.