I have a Coral Beauty in my 125g.
I feed twice a day having 15 fish (mostly small 1-3 inch), 2 anemones, 1 pepermint shrimp, and a small compliment of snails.
My coral beauty will eat from my live rock, but never the coral.
Try feeding seaweed on a veggie clip, in addition to a meaty food such as
mysis shrimp ( place the frozen cube in a fine net such as a brine shrimp net, run it under tap water until thawed, then transfer thawed food into a cup filled with your aquarium water and feed by syringe). This will allow you to feed without putting the harmful tap water elements into your tank.
I hope this isn't too much info.