Thanks guys. Teehjaeh57, Have you ever run across this white dorsal fin fungus before? So bummed since I thought everything was going great. I guess I'll see what happens. I'm not in a position right now to catch and treat them, so hopefully, the condition will resolve on its own. Big cold front rolled in last night so I went ahead and turned the aeration off until Spring. From everything I've read here, it doesn't do much good once surface temps get below 65 or so. Again, thanks for the advice everyone.
