Alas, poor Yorick! I knew him, Horatio: a fellow of infinite jest, of most excellent fancy: he hath borne me on his back a thousand times; and now, how abhorred in my imagination it is! my gorge rims at it. Here hung those lips that I have kissed I know not how oft. Where be your gibes now? your gambols? your songs? your flashes of merriment, that were wont to set the table on a roar? Not one now, to mock your own grinning? quite chap-fallen? Now get you to my lady's chamber, and tell her, let her paint an inch thick, to this favour she must come; make her laugh at that. Prithee, Horatio, tell me one thing.
He doesn't actually "talk" to fish so much as send psychic commands to them. So eating them isn't anywhere near as unappealing as us eating each other, to him it's like eating a chicken. Besides, what else does he eat in Atlantis?
Yes, I'm defending Aquaman, because the perception or stereotype of Aquaman as "useless" or "lame" is based only on the Superfriends cartoon that did not depict him the way he is meant to be. The real Aquaman is heroic, strong, courageous, kind to people and being the king of Atlantis, which controls the seas, means he owns 70% of the planet.