A second sick coral question - Kenya Tree Coral

[Baldy]

Ive got a ton of kenya trees in my tank (as you will too in no time) and every few months they go through that. theyl slump over or shrivel up into a tight ball for a couple days but they always come back. like a previous poster said, their almost impossible to kill. i tore off one that was nearing 6 inches high and the area i tore it from is growing again.