I believe I read that the fish is ocean fish ( not freshwater etc..), but I don’t have the source.Not a bad pellet, I'd say. Although being the skeptic that I am, I'd want to know exactly what fish is in there and exactly what fish by-products are there.
As for the fish by-producs, I suspect it is the legality. They use the whole fish so by default they use fish by-products.
The fish do like it and are lot more active vs. when I gave them home made frozen food. Noticeably more….