Yes, this is actually a serious question, even though I'm sure you'll probably get a chuckle out of it.
The red double-tail crowntail male I picked up on Tuesday was bloated when I brought him home, and I have been observing him in a quarantine tank (that I've actually set on my desk next to my computer so I can watch him as I type) since then. There's some shots of him here if you wanted to see him.
He's been quite stubborn though, wouldn't take daphnia, wouldn't go for the cooked pea, wouldn't eat a pellet, wouldn't even try the betta flakes. So for six days we've been at this now, no eating and no pooping.
Sat down this afternoon and as I was bringing up firefox he comes over to the corner of the tank - not unusual I thought, he follows my hand around as I move the mouse, since its near him. But then he starts wiggling back and forth while rapidly waving his pec fins, low and behold, he finally cleaned out his system! ...I shouldn't be so happy a fish can poo. xD
But then I see there's bubbles floating up around the side of the fish to the surface of the water. I tried to look closer but that apparently spooked him and off he went to the far corner of the tank.
So, I'm curious, was that a fart? I'm not really sure what else it would be, I mean, those bubbles certainly weren't coming from his mouth. But then again I also wasn't aware that a betta's digestive track functioned in such a way as to produce so much excess gas that he would need to fart. Any fish physiology experts out there want to lend a hand? Have any of you witnessed any of your bettas passing gas?