Betta with large lump under head

Question

Betta   Hi Jaymie,

I have had my male betta for a year and a half now, he has always been active and fed well but has recently (last month) developed a large lump under his head. His scales have 'stretched' for the size of the lump as it is not growing on top of them. When i look at it with light behind him i can see straight through it and see his original under body side - like it is filled with air or fluid? Originally he was behaving normally but now it is getting bigger and he is spending more time at the bottom of his tank with his tail elevated higher than his head. he is still eating and is active when i interact with him. he is in a 10L, filtered and heated (27 degree) tank by himself, with water changes weekly.

What do you suggest? Is there anything i can do, or should i put him to sleep? Any help/advice would be greatly appreciated.

Kind Regards,
Susie

Answer
Susie,
It is hard to see a lump, but I do see a very bloated fish. I cannot tell if it is fluid but the best thing is to fast him for two days. On the third day, feed him a cooked shelled pea and then fast again for 2 days. With the Betta, this problem usually happen if they are over fed, and/or if the water is bad. Since you do water changes weekly, I will say it is from over feeding. Your Betta's stomach is the size of his eye. He should be fed once a day, 2 pellets at most, depending on the brand of food. Do not feed him any flake foods. Once you have fasted and fed the pea, let me know if he is still having this problem.