My first reef tank was a 110 gallon filled with Fiji rock and just 2 or 3 of majanos in the beginning, although mine were green and brown. I thought wow, so lucky these rocks came with free corals! I even target fed them! They soon made lots of babies and then I finally read that they are pests and took lots of elbow grease to remove them with a razor blade.
These days, anything brown with stingers are sacrificed to the porcelain god.