🚀 go-pugleaf

I hope someone can help, I need some advice on what to do with a sick  
fish.  The fish in question is a Sunfish.  On Friday I noticed that the  
fish had a white, perfectly  
round circle on his bottom lip.  It looked like he might have scraped or  
bruised his lip on something.  Last night the fish was swimming a little  
crooked, sort of leaning to one side.  The fish has been hanging around  
under the filter so the water has been hitting him.  I added some  
anti-fungal medicine last night, and I also looked in the fish book, but  
did not see anything that looked similiar.

On Friday, I did a partial water change and also removed part of my UGF.   
After removing it I noticed bunches of small worms, that were living under  
the filter.  (They were rolled up in bunches).  The worms were a whitish  
color. Could this be the cause of the white circle?  Does anyone know what  
those worms are?  Are they dangerous?  Please help!  I'd appreciate any  
advice.  BTW, the other fish in the tank are Cichlids, and 2 plecs.

Thanks,

Kathy