My betta died today with a mysterious white spot on his back fin. It was there for quite a while, but he didn't seem to be bothered, but in the past week, I noticed the spot was getting thick looking, not like normal fin, or body tissue. It's not fuzzy, so I don't think it's a fungus, but it might be. Anyone have any ideas? He was in a 28gal, water amm 0, trites 0, trates 30, (tomorrow is wc day). His tankmates were 3 kuli loaches, one honey gourami, and 4 danios. I never noticed anyone picking on him or vice versa, and the only thing I see on him is this weird white spot. Look on his anal fin, near his body