Well, there are so many factors it's a shot in the dark for us, so maybe start a thread on your tank so we may see something that may not be obvious to you.
The fact you are calling them pink makes me think you may have had a semi bleached red.
They really should not need food if they are healthy, light is their main source, as long as they are healthy and have zooxanthellae to produce that light into useable energy.
Start a thread listing time running, params by number, and all gear, and maybe your issues can be solved here.
I have seen some toadstools deal w/ it, may depend on the clowns and how much they are loving on it, size of toadstool/clowns, so on.
Good luck either way.