A growing problem

[SoCal]

My sister sent me this picture of her betta and asked if I know what that is, she described it as a "bubble" and said it is slowly getting bigger.

I'm stumped, anyone...anyone?

 

[Devilishturtles]

If the fish is eating well/swimming fine, likely a benign tumor/growth of some sort. They usually aren't treatable either, because they aren't caused by anything controllable. My best advice is to keep your water as clean as possible and keep an eye out for infection, lethargy, lack of eating, etc.

 

[An t-iasg]

SoCal !! Great to see you!

Poor betta...I've never seen anything like that. I agree with Devilishturtles. I would just keep him comfortable with nice clean water and monitor him.