They re-ran the episode last night, and I watched it this time. In that bucket when he was picking through it, I did notice the back half of a fish that definitely looked like a tang, and by the colors, I agree it could have been an achilles. Not sure if they are indiginous to those waters though. Definitely saw what looked like some angels.
Well, when you're hungry and fending for yourself, fish of any type means food. I can't condemn the show for any of that.