It could be. Gastroenteritis is basically the catchall term. It could even be salmonella. I try to be very conscientious about washing up after handling the birds, but something could have gotten through. I'm not bothering to go to the Dr. to get a fecal sample tested, so I can't know for sure. The treatment is pretty much just keep hydrated and rest.
Might ask your Doc or pickup fish antibiotic for secondary infection if seeing your stomach is involved