Today I spotted some white fuzz on one of my bettas in my 10 gallon. Yuck. Parameters updated on Aquarium Info, but here they are again: pH: 6.0 or less (I've got really soft water here, so the carbonate hardness could just be really low like usual) ammonia: 0-.25ppm ... I think it looks yellow now, but my boyfriend thought it looked closer to the .25 nitrite: 0ppm nitrates: 40-80ppm ... the two colors look exactly the same to me. This is the same result I had on Friday when I did a 50+% water change. I posted the pictures of the bettas. The darker colored one is the one with the white fuzz. The part on his cheek fell off within about 5 minutes after I took that picture. Not sure if he rubbed up against something or what. The lighter one has fin rot and has had it before he was put in the tank. We're attempting to battle that with water changes and when they are fed pellets, soaking them in Vita-Chem. What is the white fuzz? Is it contagious? Do I have to do something about that beyond water changes? Should I quarantine one or both of them? Also, why would my nitrates not go down even with a large water change? I have plants - shouldn't they be eating some nitrates?