Oh I believe it. I never would have in the past...I'd been out of the hobby for probably 20 years, and when I was in previously pleco's were generally pretty shy retiring creatures who were never seen if they had adequate hiding spots. Chinese algae eaters were the ones we were warned about back then, to keep them away from the deep-bodied fish like discus, big gouramis etc. But the pleco I have now is totally different, he has no fear, he rolls over on his back and eats cichlid gold pellets etc. I wouldn't be surprised at all to find him sucking on a fish. Not sure if the plecos have changed (I'm thinking they're farmed and are learning new behaviors) but whatever, not taking the chance.