severn dam- disease?

[Trey]

just got back and what a day. fished severen dam between standard and rosebud, caught well over 30 rainbows between the 3 of us. mostly 1 lb pan frys, although im told there is way bigger ones in there. tons of algae though, and a bunch of leeches on the underside of the canoe when we took it out of there. kinda busy when we showed up, seen the usual garbage thrown carelessly on the shore here and there at most busy fishing spots. and there were some real drunk asses having a blast on the lake with electric boats. one guy kept saying something to us about a 300$ fishing derby going on, and it turned out it was just 6 drunk guys betting each other on who would get the most. they were camping there so it was all good. (i hate seeing people get on the highway after a day of drinking on the lake) one guy wanted to trade us 2 for one of our biggest so he could have bragging rights. we told him to bite it.

lots of fun today but i did reel in one rainbow that had a red lump right by the anal fin. about the size of a pencil eraser, that looked like it was bleeding however no blood came off when you touched it. and another one on the underside by the pectoral fins however this one was smaller. i threw it back cause i wasn't going to eat that. but im curious as to what that might have been?? something burrowing inside the fish maybe? a disease perhaps? any guesses? ive fished in a dirty harbor on the ocean and have seen sea lice before but this was different. any thoughts??