I have done this battle but with Monti Eating Zoa's. Honestly I think I caught it early enough to leep them limited to the colony they came in on. I bought a Yellow Coris wrasse and along with scrubbing the coral with a toothbrush to remove the eggs, and won the battle. From what I understand its hit or miss with the Yellow Coris, but the Green Seagrass Wrasse (caleb's second link) is really supposed to go after nudibranchs with a serious vengance.