Metallic Green Wall Hammer MdIt is moderately difficult to maintain, but with proper water conditions in the aquarium, it will thrive. It will require moderate lighting combined with moderate water movement within the aquarium. At night, its sweeper tentacles can extend up to six inches in the reef aquarium, stinging other species of corals and animals. Allow plenty of room between it and other neighboring corals. For continued good health, it will also require the addition of