Just because fish in the wild don't encounter certain ingredients found in processed foods off your LFS shelves don't mean it's not good, or unhealty for them. I'm pretty postive that the majority of fish kept in aquariums are pretty well fed.
I use mostly various Hikari & Omega One foods along with various frozen and live.
I'm curious..what makes salmon meal better than other fish meal?
it is un likely many of our tropical fish would ever encounter many salmon.
but after watching how greedily even fish that are notoriously picky about their food take it, theres no question about its superiority for me anymore...
Again, you can't rely 100% on the "guaranteed analysis" of foods. They guarantee that it's in there, but that doesn't mean that it is digestable. Unfortunately, not enough pet owners research into foods, what goes into the foods, what the law requires with the labels, etc, etc. I just find it fascinating, so, I dive into it all the time. Anyways, if they put old dirty boot leather into fish food, they could technically call it "meat by-products" and give it a guaranteed analysis of say 70% protein (just pulling a number out of my arse), that doesn't mean that the fish can actually digest 70% of that protein. They might only get 10% protein from that boot leather because, well, it's undigestable. Yes, it is protein, but that doesn't mean that it's digestable. Not only that, but, it also depends on the exact species of animal that you're feeding. A carnivore is not going to be able to utilize the same ingredients as a herbivore. You throw a random "tropical flake" into a tank, and some fish may be able to digest the meat proteins (whatever is digestable in that particular food), while others might be able to digest the plant proteins, but, the label calculates ALL of the combined protein, even the totally undigestable protein. That doesn't mean that they're getting anywhere near that protein (or any other nutrient) level...