Corydoras barbatus reach approx 5", most Brochis top out at ~3-4 inches and are alot heavier set than most Corydoras. Given that gold saums aren't naturally piscovorous, and that a cory is actually quite well armoured, I still think that the larger species I mentioned would be fine. Gold saums are generally not that aggressive or predatory, and he says his is placid? Sounds like it'd work to me, probably better than the smaller soft-skinned pimelodids. If you're really paranoid about it, try one of the Synodontis sp., they can hold their own with most similarly sized cichlids.