Panda cory?
Yup, corys do fart - I've observed it many times. They dart up to the surface for a gulp of air - they can extract
O2 in their gut. Then they lay on the bottom and let a few rip.

Hilarious to watch, but they won't do it if a camera is anywhere in sight.
Other normal (wierd) cory behaviors:
Laying on their sides or back as if they're dead until their owner notices and freaks out.
Mad dashes up and down the tank for no apparent reason.
Fast-paced games of follow-the-leader (if you have a group of five or more) followed by collapsing in an exhausted heap.