I think seafood based catfood would be better (the pellet food not the "soft" food) If you look at the ingredients on the catfood bags you'll quickly find the vast majority of the pellets in the aquarium hobby are overpriced cat food.
My suggestion would be one of those hollistic brands that dont use any "fillers" find some seafood based one and it should be fine. Can't guarentee anything though, and it may foul your water. Might be worth a shot if you have a cat.
I tried once just to see (iams lamb and rice) He didnt like it. Doesnt seem to like beef either. Loves fish, worms, shrimp, scallops, and anything alive.