(This is a bit of a creepy obsession.)

“Then you'd need the rest of an alive fish to keep them alive. But you could use a live animal, yes, I suppose. I think it'd be harder to learn to see through them, and the fish wouldn't look where you wanted to, and you'd have to keep it in water so it could breathe and feed it —

Frustrated arm waving.

“Made eyes are just so much easier to deal with, and they're almost as good anyway.”