Classified as a large polyp stony (LPS) coral, Hammer corals (Fimbriaphyllia ancora, once belonging to the Euphyllia Genus) consist of a hard a calcified base and puffy, tubular polyps. Hammer corals are named for the flat, hammer-shaped tip at the end of each polyp. Fimbriaphyllia paraancora, Branching Hammer corals, are very similar, but the skeletal structure will grow into separate corallites or "heads." Found in a wide range of green, brown, pink, peach, purple, blue, and creamy beige shades. Hammer corals are very popular in the reef-keeping hobby.
They can be found in a wide variety of conditions, from murky waters filled with debris to waters that are well-lit and crystal clear. Currents should be low to moderate, and turbulent flow rather than a constant stream from one direction is best. The idea is for the flow to be strong enough to get the tentacles moving around a bit and keep detritus from settling on them, but it also should never be so strong that it prevents the polyps from expanding. (You'll know an unhappy Hammer when you see one.) Providing your Hammer coral good waterflow to increase the availability of passing food will contribute to their success. Hammer corals prefer indirect, low to moderate lighting. We recommend 100-125 PAR. Bear in mind that many corals can be gradually acclimated to lighting beyond their normal range.
Through their symbiotic relationship with a photosynthetic algae, known as zooxanthellae, they receive many of their nutrients. Hammers can absorb microparticles of organic matter and nutrients from the water column. Target feeding and adding supplements, such as Calcium, are recommended in tanks that contain Hammer corals. Monitoring your water levels properly and regularly can make this level of care much easier to attain.
When introducing a new Hammer into your reef tank, please know that they can be aggressive and have a bit of reach advantage. They have sweeper tentacles that will sting neighboring corals. These sweeper tentacles, ranging in length from 2-10 inches) usually make their appearance at night. Reef Chasers recommends giving your Hammer corals at least 6 inches of space to allow for growth. The good news - Fimbriaphyllia typically get along well together. Consider placing your Hammers and Frogspawn corals in the same area of your reef tank to allow for different types of corals to inhabit other spots.