Betta with badly bitten fins!!

my Betta cosmos has bitten his tail so much he almost looks like a crow tail. he is a halfmoon with fins the length of his body. he has bitten his tail before but not to this extent, and he hasn't done it for a while.

I had him in a divided 10 gallon until today when I noticed his fins all frayed up. yesterday I came home to find the both betas in one side. there are no holes and I had made the water levels a bit to high so I assumed he jumped over. cosmos was the one chasing him around and didn't have any injuries on him. this morning I found his tail looking like string. I moved him into a 3.5 gallon that has better water quality.
I missed a water change in the 10 gallon so the nitrates were a bit high.

is there anything I can do to get him to stop/to help him heal??



when I had him for about a month and he hadn't bitten his fins before

 

How long was he in the divided tank? He might have been biting his fins out of stress. Are his fins very badly damaged? Bleeding or anything?
You can add some Stress Coat to his tank so his slime coat is in good condition. You might also try Melafix. But I've heard that if it's dosed for too long it can cause issues with a Betta fish' breathing.

 

How long was he in the divided tank? He might have been biting his fins out of stress. Are his fins very badly damaged? Bleeding or anything?
You can add some Stress Coat to his tank so his slime coat is in good condition. You might also try Melafix. But I've heard that if it's dosed for too long it can cause issues with a Betta fish' breathing.

Do you mean both bettas in one side? I suspect only for a max of half an hour and neither of them sustained much damage. If you mean separately he was in there for a good 3 weeks where he only bit his fins once or twice a week and when he did it wasn't too bad. His fins are very badly frayed, one was bitten and now has torn almost to his body but there isn't any blood. he is almost black so its hard to tell. His fin looks like a crowntails but stringier.
I'll look into stress coat but I'm weary to use melafix as I know its risky for all fish not just bettas.

 

some pics for an idea of the damage. you can't see but some of the tears are quite long




sorry for the bad pic quality he kept moving and my camera isn't too good

 

That doesn't look too bad to me. Just keep up the water quality, give him plenty of love, and as I mentioned earlier, a bit of Stress Coat might help.
Hope he makes a full recovery!

 

Ok will do! Thanks for your help

 

That doesn't look like tail biting. It looks more like his fins got caught in the filter.

 

I had him on the side of the divider without the filter and he had nothing sharp in his side. He also has a history of biting his tail

 

Weird.

 

I hope he gets better, he's a beauty!