btw i feed primarily nls and omega. and other things like bloodworms, mysis shrimp etc as treats, most of the top tier foods are great and produce good results. you can feed exclusively one "good" pellet food and get good results. Although i do still believe in variation in food types, for happy healthy and entertained pets.
However, a variety is not good for all pets. But for fish, I whole heartily agree.
Feeding too many different foods to dogs for example can cause digestive issues.