This one, admittedly, is a tough one for me to address, due to the reasons that I became vegan.
I’m personally vegan for animal welfare reasons, as opposed to strictly environmental reasons. This means I haven’t had to put a lot of effort into researching the differences between wild-caught and farm-raised fish, since I just avoid eating fish in general.
A couple things I do know:
However, fish farms do create dire invasive species problems, are potentially really gross for the planet and human health, and can be pretty cruel (see this and this). So if you’re contemplating continuing to support the farmed fish industry, you’ll probably want to look into it further.