Make sure if you feed any food chunks that they are small (like size of a pencil eraser) and so fresh you would eat it yourself.
Clown anemones can grow from the size of a quarter to the size of a dinner plate with nothing other than sunlight and whatever random food they snatch out of the water. If you feed, it will accelerate growth, but you need to be very careful about food poison. As you have read on these forums, it has become clear that these animals have very limited ability to protect themselves from internal bacterial infection.