It's only a weed if you dont like it. Started out a smalll colony on a rock, grew big, and choked out my zoo colonies. then I took the rock out and scrubbed it off, which just made them spread. Then, started growing on the coraline on my glass . I gave a whole bunch to a fellow reefer who said his green urchin and morish idol ate it. I tried a green urchin with some success. Blue hippo tang nips at it. Now its mostly gone, but only through manual removal. Remove it like green bubble algea by siphoning out spores. My emerald crabs dont touch it.