Corydora with bubble in stomach?

[connor31556]

Hi guys I have a 20g cycled tank that been up for a couple years now with adequate stocking and recently my corydora stopped moving alot and got a huge bump in its stomach. Its fins are currently clamped and its nose Brussels are broken (have been for a while, probable because of the gravel substrate) hes breathing heavy and I have recently dropped a city pellet right in front of his nose and he/she wasnt interested in it at all. I dont know if it's a girl or a boy but I do know it's not pregnant as it's been alone for a couple years now. Any ideas? Would a dip work? Thanks for the help

P.s. sorry for the bad picture the fish is not cooperating with the camera