The only really sustainable aquaculture products are bivalves and seaweed: https://www.nature.com/articles/s41586-021-03889-2

interesting: yea better cut out the middlemen and go straight for the nutrient sources. I am not really informed about the subject but farming fish still seem way less harmful than farming methane emitting cows and mrsa ridden poultry. so bivalves and seaweed it is !