[Sheldon31]

Kyon has a hole in his tail and some chunks taken out the end! I think he's biting again he's in a heavily planted tank with lots to look at and swim through. I play with him daily while feeding him. Is there a chance that adding the cories has upset him a bit and he's biting out of stress? There's no stress stripe and he's not attacking them. I've checked the water. All good, no ammonia or nitrites and just below .5 nitrates. All my decor is definitely smooth enough for him and I only use live plants. It's starting to upset me because I just want him happy and healthy. Any ideas to stopping him from doing this would be great.

 

[EmZajex]

It could be possible that the corys have stressed him out. How large is your tank? Which parts of the tank does he usually like to go to, or does he like to go everywhere? Corys usually make good tank mates because they stay at the bottom while bettas are top feeders but if they tank is anything less than 5 gallon then this will definitely stress him out. Every Betta reacts differently. What has caused him to bite his tail before?