There are huge differences in quality when dealing with farm raised fish. Those raised in aquaponics systems can be quite clean and environmentally benign.
Shrimp from Asia is produced in a horrible manner. They fill saltwater ponds which leach into the ground
water and pollute it.
Bassa from Vietnam is raised in giant craters along the Ho Chi Minh Trail which were created when B-52s bombed the area. Agent orange has left this area as one of the world's worst places for birth defects. Fish produced in these ponds is shipped around the world.