My wild caught Sunfish (Bluegill, I think) has develpoed whitish blotches of something on the fins. The fins seem to be breaking down and are deteriorating at the ends.
it looks (to me) like lymphocystis . . . if it is, you could excise the damaged area, but I'm not sure there is any other treatment (except time), and it is contagious
Without even asking for further queries, please don't suggest anything that you think will rectify the issue.
If this is lymphocystis, does the affected area feel hard and globular assuming these are cysts that are creeping up? Your only option is to prevent it from spreading towards the body of your fish by trimming the fins carefully with sharp scissors but the affected anal fin is very tricky. Make sure the water quality is clean to allow the fins to regrow without the viral infection interfering.
Very odd, looks a bit like a secondary fungus infection.
Lupin, I didn't know you can actually trim off the fins.. but if it will grow back then it is good to know when I get fin rot to stop it eating up the fin.