SF Bay Brand krill is harvested from Arctic waters and contains extremely high amounts of omega-3's (about 40% of the total amount of essential fatty acid found in krill). Also found in high amounts are methionine and lysine, amino acids that the fish cannot produce themselves so they need to be present in supplied foods for optimum health. Krill contains astaxanthin, a carotenoid easily metabolized by most fish species and is responsible for the vibrant colors of tropical fish.This is an excellent alternative to feeder fish for large freshwater and marine tropical fish.