"Papa Red" wrote in message
...
I have a Betta who is a wee bit obese,... And I'm wondering if it is
really fat, or could it be a tumour of some kind.

First of all, how long has he had a swollen belly? If it has developed over
a short time, he's probably constipated. Is there evidence that he's
excreting regularly? Try feeding him a tiny piece of defrosted, de-skinned
softened green pea once a week, instead of his usual food, or give him
daphnia weekly or fortnightly. If you think he's constipated and the green
pea doesn't work, add epsom salts to his water, at a dose of 1/4 teaspoon
per gallon, and leave it in for up to 3 days.

How much do you feed him? Bettas can get overweight, particularly if
they're inactive. Overfeeding with pellet or flake food can also contribute
to constipation.

Dropsy is another possibility, particularly if the swelling developed
suddenly. Keep an eye on him in case he gets bloated looking all over, and
his scales start to stick out like a pinecone.

Vicki PS