[Myka]

Pet food manufacturers only have to label what they add to the food. When they buy an item for the food, say "fish meal", the manufacturer doesn't have to list the ingredients the supplier added the fish meal, just "fish meal". This problem arises in dog and cat foods mainly because those foods are much more popular and inspected more scrupulously by the consumer and the PFAC. Taking "fish meal" as an example again, many suppliers add ethoxyquin (known carcinogen used as a preservative) to their fish meals, and the manufacturer doesn't have to list ethoxyquin as an ingredient on their label. That ingredient is one of the bigger "hidden ingredient" concerns in dog and cat foods.

I have a feeling that people (manufacturers, ingredient suppliers, consumers, and the PFAC) in very general terms care about their fish foods less than their dog and cat foods. There is a lot of garbage that makes its way into dog and cat foods; I can just imagine the garbage in fish food.

In the end, the best option for your fish's health is probably using raw human-grade seafood and seaweeds supplementing daily with a proven vitamin supplement like Selcon.