Ram Cichlids, for example, cannot gulp a small fish like Neon Tetra because they're small themselves (well, small as for Cichlids). Ram Cichlids are very beautiful too

But other Cichlids ... yes, they may eat smaller fish. Although I have raised 2 Angelfish from babies with Neon Tetras, and my Angels have never bothered the Neons. They just ignore them as if they didn't exist. BUT ... if you put adult Angelfish (that have been raised up with other Angelfish or otherwise other fish as large as themselves), they certainly CAN eat smaller fish like Neons.