My mother has Majano ALL OVER HER AQUARIUM. She has a 210 and they killed a couple thousand dollars in corals all she has left now is fish. I talked to the LFS about them, They said that Raccoon butterfly fish will eat them. They will also eat aiptasia. The long-nosed butterfly fish will eat them also but are more likely to eat corals. They are extremely hard to get rid of my Mom has baked her rocks in the sun, the second they hit the water they were back. I would find a solution quickly because they can and will wipe out your tank!!! hope this helps a little bit. (did not mean to scare you either)