Switch to frozen food. Go to your fish store, or any Petco or Petsmart, and they will have frozen food in a freezer. Not only is frozen food more nutritious and delicious, but pellets and flakes contain ash, which leads to algae problems. If someone is having an algae outbreak, often the easiest change to make is to switch to frozen only.
If I were you, I would pick up some mysis shrimp cubes. See how the clown takes to that.