Kids go nuts for mcds too! It's not exactly bad for them but too much is. Broccoli is way better for them but they don't want to eat it so much. It's the same with the fish. The only way you can tell is look at the ingredients. But then you have to understand what those are and if they are good or not. Most of the ingredients should come from the water krill, whole fish, kelp, seaweed, algae, those should also be the first ingredients. Ingredients in food go in order of what makes up most of it to the least. Most foods will contain wheat or something like it when was the last time you saw a fish able to get wheat in the wild? It has to be there but shouldn't be in the top 4 or 5 ingredients. Just stuff like that. If by ingredient it sounds good it probably is. Less land based the better.
I once saw this little girl at Walmart who was eating broccoli like it was a candy ??. Should have asked parents what's the secret.