Introduction to the Hammer Coral

Euphyllia fimbriata, the Hammer Coral, is a beautiful LPS coral, one that is a big favorite of marine hobbyists. This Euphyllia spp. is not found in Australia but does resemble one of its closer relatives the Anchor Coral, Euphyllia ancora of which the Hammer Coral is often confused with and even the Frogspawn coral. With close inspection, you are able to quickly identify it properly.

The Anchor Coral and the Hammer Coral are very similar corals; however, the Hammer Coral has polyps that are “T” shaped at the tips. The Anchor coral does not have the “T” shaped tips, but instead has semi-circular or even sausage shaped tips.

Hammer Corals do have straighter and flatter tips, they can also have a curvature in the tip. Some corals in the genus have some nice branching characteristics e.g. Euphyllia parancora.

A Green Tip Hammer Coral

Hammer Coral Quick Facts

  • Experience Level: Intermediate
  • Hardiness: Sensitive to poor water flow and direct lighting
  • Minimum Tank Size: 50 gal (190 L)
  • Lighting Needs: Moderate – Strong diffused light – No Direct Light
  • Temperature: 74° – 83° F (23° – 28° C)
  • Gravity: 1.023 – 1.025

The Hammer Corals identification is determined more by the shape of theirs tips rather than their delicate skeletal structures. It can be found in both green and brown in color with green or cream tips. These are another one of the easily kept, very attractive LPS corals that will stick out in your aquarium, especially with some nice lighting.

The Hammer Coral is an easily cared for coral. Like others found in it genus, it will be one of the first corals to let you know you have poor water quality. A healthy Hammer Coral will rely on sufficient lighting, a moderate and turbid water flow that will allow the capture of passing food.

It has been well propagated in captivity. They are not hermatypic which means they won’t contribute to the structure of the reef. However, in the wild, it will take 2 years for a colony to repopulate and therefore there is a concern from conservationists about the collection of these corals from the wild. Some countries have outlawed the collection of it and propagating these in captivity could seriously support the future of the species in the wild.


The Hammer Coral is mostly determined by the shape of its polyps more than from its skeletal structure. They form large colonies made out of corallite walls which will form on the outer edges, and the polyps having the ability to retract fully into the corals skeleton. Polyps from the Hammer Coral will extend during the day but only partially at night.

The Hammer Corals Tentacles have a “T” shape at the tips. It has much straighter and flatter tips when compared to its close relative, the Anchor Coral whose has more “C” shaped tips or sausage shaped with curvature in the tips. Tentacle color will be either brown or tan with cream or green tips. When they are feeding, each tentacle can elongate from 2 – 3 times its normal length. There have been some colonies found reaching over 3 feet (1 m). Their lifespan is currently unknown.

A green and brown Hammer Coral


A healthy, well fed aquarium with live rock is required for the Hammer Coral. Fish creating organic material will also be beneficial for them. It is recommended, as with all corals to have a mature tank before adding them.

The appropriate water flow is medium, as too strong of a flow will damage the polyps and cause them not to extend fully resulting in poor health and eventual death from starvation. Sufficient lighting is needed, which for the Hammer Coral is indirect bright light. Do not place them directly underneath metal halides as this will damage their polyps leading to RTN.

Ensure that no other corals are able to come into contact with any of your Euphyllia. This coral can be aggressive, most often when they are feeding as their sweeper tentacles can reach out to 10” (25 cm). Feeding them on a regular basis will help prevent them from sweeping too far.

Hammer Coral Aquarium & Parameter Checklist

  • Minimum Tank Size: 50 gal (190 L)
  • Lighting Needs: Moderate to Strong diffused light. No Direct Light
  • Temperature: 74° – 83° F (23° – 28° C)
  • Specific gravity: 1.023 – 1.025
  • Alkalinity Levels: 3.2 – 4.8 MEQ/L (8 – 11 dKh)
  • Calcium: 400 – 450 ppm
  • Phosphates: 0 (Avoid Phosphates)
  • Magnesium Levels: 1200 – 1350
  • Strontium Levels: 8 – 10
  • Water Movement: Moderate
  • Tank Region: Any, provided you meet the water flow and lighting requirements

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The Anchor Coral is very similar to the Hammer Coral


The Hammer Coral is rated as being easy to moderate to look after. Providing sufficient lighting and a good turbulent water flow that is medium strength is important. The presence and availability of passing food will heavily contribute to their success or failure in your tank. Play with placing coral specimens in different parts of your tank to see which spot their favorite is. This will be seen when they fully extend their polyps during daylight hours and for feeding.

During collection in the wild, they are quite often broken off from parent colonies. A wild specimen may have some soft tissue damage. Their skeleton can be splintered and up into the fleshy polyp area damaged. When choosing a coral for purchase, ensure it has been in the store for about a week or more and has been doing well before taking it. Being cautious like this will help avoid buying any sick or damaged coral as ailments can take some days to show.

Foods and Feeding

The Hammer Coral, as in other Euphyllia corals and other LPS corals have developed various feeding methods. Planktonic organisms and microscopic food particles will be captured from within the water column. Dissolved organic matter will be absorbed as well. They have a symbiotic relationship with marine algae, also called zooxanthellae from where they can source some of their nutrients as well.

In your home aquarium, mysis shrimp, brine shrimp, krill and other smaller foods can be fed out. Hammer Corals are able to eat much larger chunks of foods as well. Chop up or dice pieces of shrimp or whole fish and feed the whole thing to the coral. Different parts of the organism have different nutritional value, so providing all of it is important. This coral is generally hungry a lot so plenty of various foods will ensure a healthy coral is maintained.


Euphyllia corals can often be quite aggressive when they touch other corals, so they should be kept away from other species.

The Hammer Coral is known to be peaceful towards its own genus but other genera from its family may be attacked. When they are hungry, they will send their sweeper tentacles out which can reach over 10” (25 cm) in larger colonies. This is a big threat to nearby corals as they have a strong sting to them. Regular feeds will help avoid this, so they don’t feel the need to search for food.

Some commensal shrimp will be given protection by its tentacles as they branch out and sting corals nearby in order to make room for its own growth and the occasional meal. The Hammer Coral is known to be quite sensitive when placed in aquariums that have large amounts of soft corals, with a specific sensitivity towards various Sinularia species.

Breeding – Reproduction

Unfortunately, the Planula Larvae are very vulnerable to being eaten and only very few will survive.

Species in the Euphyllia genus will also reproduce asexually. When in captivity, The Hammer Coral will bud off small polyp groups that have little skeletons attached to them. They will also pinch off some of their own tentacles which will then float away and as they are sticky they will attach somewhere new and bring to life a new colony.

In order to propagate these, you will need to start by choosing a healthy Hammer Coral that isn’t showing any signs of ill health or stress. Propagation is recommended to be done with an electric saw at least 1 ½ – 2” away from the top. Avoid using bone crushers or scissors as this can cause splintering of the skeleton and polyp damage. Once fragged, attach it to a rock or plug. Coral cement or epoxy are good choices for this. Ensure that the slime from the coral does not come into contact with other corals in your tank as this will damage them. You should always wear gloves when doing this. Ensure new frags have ample water flow. Polyps will remain closed for a while before slowing opening as the new frag heals.

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