Followed one of these around as close as physically possible while holding a fish corpse. So close that the "feed fish" gray text was on screen, but never turned blue like when feeding a basilo. Also clicking the action buttons wouldn't feed it at 0 range. Woohoo looks like I'll have to force tame it or spawn a tamaed one. I love having to use console commands to make up for developer durpery. That's probably why they're in the game tbh.