Related to prior question - how long can one fish survive in the belly of another?

I've seen bass spitting up smaller fish alive for quite a few minutes after eating them already. How long can one fish survive in the belly of another? Unlike a mouse in the belly of a snake (a prior question I had), fish aren't necessarily swimming in a vat of concentrated stomach acid, and don't have to have air to breathe. As long as the fluids around it are sufficiently diluted, I'd imagine it could stay alive for quite some time. :-?