Kent, Welcome to Canreef.
The Chromis is a great way to tell if the Frogfish needs feeding. When the Frogfish starts to show interest in the Chromis I know it is time to feed the Frogfish.
When the Chromis disappears I will know that I waited too long
I find the Frogfish more active and easier to feed frozen silversides with a live fish in the tank.