https://marco.org/2009/05/21/i-didnt-address-fish-because-i-dont-really-like
I didn’t address fish because I don’t really like it, and eat almost none of it anyway.
I don’t know much about industrialized fish production, but the little I’ve heard sounds like it’s really not much better than land-animal production. It’s generally healthier than meat, at least.
Moderation is still important — I think it would be self-defeating to stop eating cows and chickens and pigs for ethical and environmental reasons, only to eat fish twice a day as a replacement.