Saxamo!

Euphylla Ancora, also known as Hammer Coral, Ridge Coral, Hammerhead or Anchor Coral, is a large polyp stony (LPS) coral. Its common names are derived from the appearance of its hammerhead or anchor-shaped tentacles. Its polyps are visible throughout both day and night and hide its skeletal base. They breed via fission, which is a form of asexual reproduction and each resulting fragment produced is capable of growing into an individual.

Hammer corals may be green, tan or brown in color, with lime green or yellow tips on the ends of its tentacles, which glow under actinic lighting. Some varieties of hammer coral may be branched, which makes them look similar to Torch Coral. They can appear semi-transparent when well expanded. Hammer coral colonies may form continuous cover over the substrate many meters across, although individual colonies are seldom over one meter across. Large colonies are usually found in shallow environments exposed to moderate wave action. Hammer coral does well within a range of at least 75 to 84 degrees and prefer moderate light. (A good example of moderate light is a 65 watt light over a 25 gallon aquarium).

Keeping Hammer coral in a saltwater aquarium is not recommended for those new to the hobby. This is mostly because their delicate nature makes them rough shippers. Hammer corals have sharp skeletons that are covered in extremely thin tissue, which is inevitably easily scuffed by shipping. All Euphyllia should be given plenty of room to expand in an aquarium setting. Sweeper tentacles extend several inches at night and can sting other corals.

Hammer Coral Aggressiveness and Feeding
Hammer coral can expand considerably from its skeleton and has sweeper tentacles that are up to 2″ longer than normal tentacles that can sting its neighbors. Hammer corals grow fairly quickly and to a large size. It is photosynthetic and does not need to be directly fed, but will take small meaty foods if offered. Hammer coral is aggressive toward the other marine aquarium invertebrates.

Zoanthids are unique in that they incorporate sand and other small pieces of material into their tissue to help create their structure. In the wild, Zoanthids often occupy fringe environments (intertidal, back reef, other shallow areas, over dead corals), making them quite a hardy choice for the reef aquarist. Found most commonly on sandy reef flats and hard bottoms in shallow or deep water, Protopalythoa feature the largest polyps of all the Zoanthids. Surrounding each polyp are tapering tentacles resembling eyelashes or “venus flytrap” structures, which similarly help close in on captured prey.

Easy to maintain,  Zoanthids Polyps require a medium light level combined with a medium water movement within the aquarium. For continued good health, they will also require the addition of iodine and other trace elements to the water. They will reproduce easily in the reef aquarium by budding (splitting off a portion of their base or mouth), which will increase the size of their colony. They contain the symbiotic algae zooxanthellae which provides some of their nutritional requirements. They will also benefit from additional feedings of microplankton or brine shrimp given to each individual of the colony.

Received December 20, 2007:
A case of human poisoning by palytoxin after contact with zoanthid corals (Parazoanthus sp.) in an aquarium through skin injuries on fingers is reported. The clinical symptoms include swelling, paraesthesia and numbness around the site of the injury spreading over the arm, but also signs of systemic poisoning such as dizziness, general weakness and myalgia, irregularities in the ECG and indications of rhabdomyolysis. Symptomatic treatment consisted of infusion of physiological fluids. The patient recovered within 3 days. Analysis of the zoanthid coral involved revealed extremely high concentrations of palytoxin (between 2 and 3 mg/g).