hello. i'm kinda looking for help with the fin rot, fin loss situation. i have two bettas. one male and one female. they are in a 2.5 divided gallon tank. i got both for christmas and i noticed that my male had fin rot. so we went to the store and got tablets for the tank. they worked wonders. white patches cleared up and everything was good with my male. well yesterday while feeding them i noticed my male, a halfmoon had lost the middle part of his back fins. but everything else is fine. no sign of fin rot, he is eating right, water changes every week and partial water changes every other day. the fin was not torn, and honestly it looks like a clean cut.
anyways, so i changed their water yesterday as soon as i finished feeding. put another tab in the water and added my water conditioner. i have gravel and rounded rocks and one plant on each side. nothing really worries me except for the gravel. my male does have a tendency to go chill in the corner at the bottom for some reason. he doesn't do it much or for long but i figured it might be something to consider. anyways, any help would be greatly appreciated.