FISH WITH BULGING possible TUMOR

Question
Please tell me what my japanese fighting fish has. There is a round balding
tumor-like bulge right under his top wing, half on his body, and half on his
wing. He still has an appetite and eats all his food but with great struggle. He
has been lying at the bottom of the bowl and it looks like he's in a lot of pain
when he swims up or around. Help me figure out what to do!

Answer
Hi Alana,
I don't mean to be so blunt or anything, but unfortunately it sounds like your betta has a tumor indeed. Of course there is nothing you can do except try to keep your bettas comfortable as possible. Make sure he is able to get air comfortably, if not lower his water level, and provide plants for him to rest on. Make sure he has a good diet and it able to get his food OK. And always make sure he has good clean and warm water. Plenty of water changes as often as possible are best and try to keep his water temperature reasonably stable at around 78-80F.

This is common in bettas. I'm really sorry. If you think he is in too much pain sometimes the best thing to do would be to humanely euthanize him. Some people advise putting the poor fish in a small bag of his water and into the freezer but a much better method is to use actual anesthetic to put fish to sleep much. Clove Oil is a well-known and tried and true fish anesthic that can be overdosed to gradually put the fish to sleep forever. You can read more about it here-
http://www.nippyfish.net/euthanasia.html

Best of luck and I'm really sorry again... :(
Karen~