I have a 29 biocube that had a terrible invasion. I pulled, I yanked, I cursed...........then I tried a small Yellow tang, took it back and tried a small Scopas tang, took it back, neither of them touched the stuff. Then got a small Foxface. It devoured the Caulerpa. I bought it at about 2.5 inches and took it back at about 3.5 inches. I have done this three times. My tank is Caulerpa and Foxface free right now. If it comes back I will get another small Foxface to deal with it. I love that fish they are peaceful, reef safe IME and Caulerpa eating machines!!!