Depends on the fish. Mine has been with a large marble cat and he was plenty small enough to get eaten for a long time, but was never bothered.
I also had a 3" driftwood cat that would come out and night and swim with all the large catfish. He was there for several years, and though it's a possibility he got eaten I'm assuming he just died since he disappeared when he would have been around the right age to have reached the max listed lifespan. I never found his body but he slept wedged tight into driftwood, so that doesn't mean much.
Regardless, I wouldn't trust them not to eat him. It's a good possibility. If they're like my bullhead they'll eat any fish small enough to fit.
