Betta Problems
try taking him out of the tank for a couple of weeks and see if it gets better. if that doesn't help try treating him for tail rot. have you noticed any white spots on him or other fish in the tank? if so it could be ICK which needs to be treated
good luck
Well it is possible that he is bitting his own tail but it could as well be another fish. But another thing is that betta's do not like to be around other fish and they do not like big areas. I suggest u get a small tank like a fish bowl becasue my cousin had her fish 2 years b4 it died and it was by herself and in a sall tank..
i have had my platies bite my other fish(s) tails so it most sertainly could be that
Personally, I have never seen any of my other fish or my two Bettas go for their own tails.
I'm assuming the tail fins are torn? Bettas have very delicate fins and they can be easily ripped on decorations, fake plants, or the filter intake can do some damage to them. This type of damage should heal on its own. Just make sure the water stays clean.
If this continues your other fish may be nipping at your Bettas fins. Betta fins are very attractive targets to fin nippers. That's why I keep my Bettas seperate. If I did add my Bettas to a community tank, I would add them to a tank larger than five gallons.
ditto nosoup...it could be finrot or just he is biting his own tail
you can see a vet about either one of course :)
Your tank is over crowded. A 2.5 gallon (which is half the size of yours) is just enough room for one Betta. Then you add all the other fish. You need to upgrade to a bigger tank. When you over crowd a tank the water tends to get dirty more often. You will need to do more partial water changes and vacuum the gravel more often to keep the ammonia levels down. The fish per gallon rule is incorrect unless you are talking about very small fish such as neon tetras.
Get a bigger tank and the fin rot on your Betta should clear up.