I have 4 bettas - all of them have the same problem with their fins/tails. They're all veiltails, and their tails always hang down and sort of curl over like they're a curtain draped down onto the floor. I keep their water really sparkly clean, so I don't think it's a water condition - I have yet to figure out what it is. I know it's a mild case of finrot, but it never gets really any worse or better. ooh it drives me nuts!
BUT... if you wanna try some meds for your boys, you could try the MelaFix, although i've never had any luck with it and I"ve heard that when it does work, it takes its sweet old time. The benefit to it is that it's more of a natural herbal remedy than harsh meds. If the tails aren't deteriorating really fast, you might give it a try. Otherwise you might want to try something stronger like Maracyn or something.
Aquarium salt is a great healing agent also.
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