Due to the appearance of its hammer- or anchor-shaped tentacles, it is called Hammer coral or Anchor Coral. Its polyps are visible in green, tan or brown color along with lime green or yellow tips on the ends of its tentacles that glow under actinic lighting and give it an amazing look. Sometimes, the Hammer Coral is misidentified with the species called Torch Coral for having similar branched polyps. Its polyps are generally open and visible during the day, and at night it retracts and hides into its skeletal base. The Hammer Coral mainly gets nutrition through photosynthesis which is done by the entrapped algae, Zooxanthellae, present in its tissues. It needs a supplement of calcium, strontium and other trace elements for its health and wellness. The Hammer Coral is moderately difficult to maintain, but if provided with proper water flow and lighting conditions it thrives well. It is semi-aggressive in nature and features nematocysts or sweeper tentacles that extend up to six inches, stinging its neighboring corals. Therefore, it is advised to keep the Hammer Coral away from the existing corals in the reef tank. We suggest you to provide them their own niche, as it is aggressive in nature. Also, make sure if any damage is caused by crabs, shrimps or other fishes, it should be immediately attended because it can cause a ?brown jelly? infection which can then spread to other corals. It is very easy and simple to propagate the Hammer Coral.