Hi, I have a male betta that I've had for a little over a month now. I've had no problems, and the cycle started and was going well. Earlier this week, I was cleaning out his tank and I decided to wipe down his filter which I hadn't done since I got him. Just the plastic inside parts, not anything with the cartridges. 2 days later, about half of his back fin is missing, and it's all white on the ends. I immediately changed his water and put some prime in stability in thinking maybe I crashed his cycle. I've been keeping it very clean since then and putting stability in. Ammonia is at 0, Nitrite is at 0, and Nitrate is at 10. Now, even more of his fin is missing and it's still white. Please, I don't know what I'm doing wrong. I'm really worried about him. Thanks.