As fish heal their wound often seems to itch, this may be a reason for the
biting the tail.
I would put this betta in water with NO nitrite or ammonia present in it.
finrot is caused by less than great water
so 1) fix your water!
2) try get the poor creature some live food, like mozzies or brine shrimp

It really is important to get this fish is good water!
At the very least start taking a cup of water out each day and replacing
with a fresh cup.
the cup a day water dilution is a good way to get the water in better order!
remove any rotting food too
your fin rot is almost certainly being caused by ammonia in the water
burning the fishes fins.

It would help if you could explain how you are looking after this fish,
water changes (amounts and frequency), filters, tank size......
those bits of data are how we can help you




"Beano" wrote in message
oups.com...
I have recently acquired a halmoon male betta who insists on chewing
his tail. There are some areas of the tail that appear to have
finrot, and some injured from chewing. His past owner and I both have
witness him chewing.

I am currently in the process of fixing the finrot, but this has been
done in the past by his original owner and the chewing still persists
in the absence of finrot.

My question is, is there a way to stop him chewing?! It would be nice
to able to see his tail grow back, even if it's not the same as it
was.

Thanks.