Balloon-Bellied Betta
 

I've noticed for about 2 or 3 weeks that a male betta in the tank with some zebra danios and an oto has grown a balloon belly. Now, I know that he's not pregnant because he's a guy, bettas need both a male and female, and there's no female in the tank with him.

So, what's causing him to get a big belly?

What and how often are you feeding him? Bettas can and do suffer from constipation and when mine does (overfeeding on my part :oops:) a few small meals of fresh frozen Daphnia works wonders.

I thought I might have been doing that, so I started feeding him less, and even have skipped a day or two with feeding him. His belly still seems to become almost see-through at some points.

Dropsy perhaps? Can bettas get dropsy?

looks at this if you think it might be dropsy Betta Fish Dropsy

I think its constipation as others have Said , Try feeding fresh/frozen Daphnia in small quantities untill you see a bowel movement.

~Quarantine him in a bare bottem tank if possible, that way its easier to see if hes having any bowel movements or not
I Hope he recovers well.

If its dropsy and hes started pineconeing, not alot can be done I'm afraid, all you can do is keep him as comfortable as possible,

Epsom salt bath for 15 to 20 min is sometimes helpful. Water changes once a week.

I do Epsom Salt baths as well. I've tried Daphia before, but it's so tiny my Betta never sees it. Epsom Salt worked like a charm for me twice.

Try the frozen/Freeze dried stuff , he might see the freeze dried or frozen stuff better.

Frozen Daphia is what I feed all my fish (among other frozen foods). Everytime I try to give it to my betta, he doesn't see it. I'm not concerned though. He hasn't been bloated in a long time, now that I know the reason that caused it :-)