Some people stop feeding corals if they have shrimp because shrimps can do more harm to the corals than the feeding is helping. I have seen cases people report here that shrimp digging trough the coral tissue to reach corals stomach contents.
Personally, I chase shrimp away from the coral with a long stick and try to feed them in midday when shrimps are less active. Now they are afraid of the stick and hide as soon as i put it in the water.
You can also cut the top half of a plastic bottle off, remove the cap, feed the coral and put the cut-bottle over the coral until it eats . After that you can remove it.
(or you first put the bottle and feed the coral through the cap)