It depends on the species. There's around 25 of them, some difficult to impossible to keep, some easy. I've had one for about 3 years now, and it's apparently one of the easy ones to keep. Unfortunately it's very difficult to tell which species you have without looking at the skeleton, as many of them look nearly identical. I have heard that the ones that grow in spherical shapes could be the difficult ones to keep. Mine grows in an oblong shape on the sand bed. My red coris wrasse is constantly flipping it over looking for food. I can flip it back, but within minutes the wrasse flips it over again. This doesn't seem to bother the coral, nor do my percula clowns bother it. They occasionally swim in its tentacles, but prefer a toadstool coral for their home and always sleep in that.