LOL, I learned the same lesson. I have 3 bluegill and blue catfish in my aquarium. Few pieces of the busted up pellets still float, lot of them settle on a flat rock on the bottom and are still quickly eaten. It is all the "powder" that messes up the aquarium bottom.
I use Purina Gamefish Chow that has several sizes of pellets, so I sift out the smaller ones for the bigger fish (3" bluegill, 6" cat). I got the aquarium specifically to learn these lessons. Larger one with a bass is hopefully coming in the future.
I also tried pre-soaking the pellets before throwing them out. I use a 32oz plastic cup to carry the fish food to the pond, so I just fill it up with water and wait a little before throwing it out. I did not try this in my aquarium. Wet fishfood is better for your fish. Friend of mine is into fish farm equipment in Norway. They found dry parts of pellets in the fish excrement, so he invented pellet soaking machine
