My son caught fish with numerous lumps on it at Beaver last weekend.
We released it and it swam off, sounds like you either caught it or there are more like that one out there. I would bet the latter. Last year we had seen a number of very sickly looking fish swimming on the surface slow at Beaver. Even the Bald Eagle wouldn't touch that one.
If you put 10,000 fish in a lake that size you're pretty much guaranteed to incubate evil. Mind you that can work in your favor if your kids get bored easy and the fish are easy to catch.
I had promised him we would smoke some of the trout we caught for his grandparents but there was no way we were going to smoke that thing with bubos on it. It lead to an interesting discussion about the bubonic plague. I am no longer in favor of eating fish from that lake. Not to mention a certain German sounding dude in a tin boat with his partner appears to catch numerous small fish from there, eat them and return many times over. With each return his voice becomes louder and more Teutonic sounding, singing the praises of power bait:
"zis power bait ist sehr gut mein freunde, dieses fish gegessen mein Power Bait Jetz...besonders...also...gibt das heir mein kartoffel chip....Ja Karl, hast du eine altes fish mit Bubos...alles gut der Kommiser..essen deine fish mit bubos jetz, gibt das here, machen sie gut und supermench..."