I got my rose tail betta in April and he was doing great at first. About a month ago, I noticed that he seemed to be having more issues with his tail with quite a few splits and some deterioration of the dorsal fin as well. It looked like fin rot and continued to worsen, so I treated it with Furan 2 which temporarily improved his fins. Now his fins are looking even worse than the first time, so I started the Furan 2 treatment again. Currently on day 3 of treatment and noticed this weird looking white ball between his ventral fins and I'm worried that it's a weird parasite that I can't find any information on (in pictures attached, water looks yellow from the Furan 2 treatment). I'm also worried about needing to treat him for fin rot all the time since he is a tail biter. I have a very low flow filter too since he struggles with pretty much any flow. He's in a 5 gallon, heated to 81 degrees, and pretty heavily planted so he has lots of places to rest. Water parameters are GH 60, KH 80, PH 7.2, 0 nitrite, and 10 ppm nitrate. There are 2 amano shrimp and a mystery snail in the tank with him since he is very peaceful and they don't bother each other. The tank was cycled for a month before I put any of them in. I do 25 to 50% water changes weekly, but I have been doing them as directed for Furan 2 treatment. I feed him daily with a variety of freeze dried blood worms, brine shrimp, and betta flakes and I fast him one day every week or two. Any advice on what this weird white thing is and how to keep his fins un-shredded?