Hunting & Fishing Black Spot Parasite on Fish

I think I have seen what you’re talking about, typically on panfish in some lakes in northern Minnesota. What it is and if it can be treated, I have no idea, but am interested in what it is. I know we still ate those fish.
 
Look up black spot disease. It’s a parasite. Infected catfish look like they have 1/8” ink spots on them.

A bird eats an infected fish, it grows in them and is passed to the water through their droppings. From there it goes to, typically, a snail and then to the fish when it eats the snail. Infected fish are supposed to be ok to eat if cooked enough to kill the parasite. This is just based on what I’ve read on it yesterday, so I could be misinformed. We caught 5 or 6 catfish yesterday and all had it.