Hey,
My betta Fuego just showed up with a large swollen spot under his front fins. For a while there he was so swollen his scales stuck out around his gill area. He no longer has scales sticking out but he still is slightly swollen. Could this be a tumor? I don't have pics, and I haven't managed to get a chance to run my water tests this week. I did read some info that said that some bettas could take more than three betta bio gold pellets a day, I fed him eight (stupid me). He swelled up then but I hadn't noticed when I very first got him wether he was swollen around the front lower fins at all. I also wonder if maybe it might be because he still has some pellets left in his belly to digest. I have not fed him for a day now, but college is keeping me hopping. I will post my tank info when I get home.

How long have you had him for?
He sounds like he might still be a bit clogged up with pellets. I hope thats what it is anyway

I agree with Lucy, from the way you describe his feeding recently it sounds like he may be a bit blocked up, if not constipated lower down.

There are other causes of swellings, but this is his stomach region so I think the most likely cause based on what we know so far is overfeeding. You've only had him a few days if I remember rightly, have you noticed any poop?

In any event, it won't hurt to starve him for a few days to see if things start to move through. Let us know your other tank info when you can so we can try to exclude other stuff

MrBumblebee is right. He probably is constipated. Hard to tell without pics. Starve him a few days like he suggested and then you can feed him a cooked deshelled pea just like you would a goldie for contipation

Thanks, I starved him for a bit and the lump went away. Live and learn. I'll never feed him that much again.

I'm glad Fuego is better, feeding fish can be trial and error sometimes so don't feel bad. Now you know the feeding habits of your Betta, it will be easier