Fun Hammer Coral Facts For Kids

A hammer coral (Euphyllia ancora) is a kind of large polyp stony coral (LPS coral) and can also be called an anchor coral, a wall hammer coral, or a sausage coral.

These corals, although aggressive in their behavior towards other corals, are extremely beautiful and colorful owing to their hammer-shaped tentacles which can be gold, green, neon green, or purple with white borders. These species of marine animals are stony corals or hard corals, which means that they build can their own skeleton.

An individual polyp is usually very soft and once it settles, it secretes a chemical called calcium carbonate, which helps grow a skeleton to protect the polyp's sac-like body.

This species of corals can grow in either of the two formations: a branching formation or a wall formation. These corals are very popular among reef aquarium enthusiasts as they are not very difficult to care for in terms of water quality, water flow, feeding, lighting, and temperature.

Most of all, the hammer corals are a breathtaking attraction to a reef tank.

The natural habitat of hammer corals around the world is at great risk because of a number of threats ranging from climate change and ocean acidification, to the aquarium trade, chemical fishing, and diseases like brown jelly. These have led to this coral species being listed as Vulnerable by the IUCN Red List.

If you find this interesting, check out more facts about other marine animals from our giant green anemone facts and ghost shrimp interesting facts pages.
 

Hammer Coral Interesting Facts

What type of animal is a hammer coral?

The hammer coral (Euphyllia ancora) is a type of coral, more specifically an LPS coral.

What class of animal does a hammer coral belong to?

The hammer coral or the anchor coral belongs to the class Mammalia, family Euphyllidae and genus Euphyllia.

How many hammer corals are there in the world?

The total number of hammer corals in the world has not been quantified yet. However, it is said that it is commonly found within the range of its distribution.

Where does a hammer coral live?

The hammer coral is found in the tropical waters of the Indo-Pacific Ocean, spanning from the Maldives in the Indian subcontinent to the western and central Pacific Ocean. This species of corals are most commonly found in the Great Barrier Reef, as well as the reefs and islands of Indonesia, Australia, and Japan.

What is a hammer coral's habitat?

Colonies of hammer corals are found in the reef slopes, reef lagoons and at the top of plateaus beneath the ocean surface.

This species is known to live in depths of up to almost 100 ft (30 m). The colonies of these corals can grow very large in some sheltered areas which have a moderate water flow.

However, the quality of their habitat is declining due to the many consequences of climate change such as the rise in sea surface temperature, which has led to the rise of many coral diseases like brown jelly, and increased chances of coral bleaching, which is extremely harmful to corals.

If they are to be kept as a pet in an aquarium, they will need a tank that can hold at least 30-50 gal (75.7-189.2 l), in which they will need to be placed either in the bottom or middle region of the tank.

The water in the tank should also resemble the saltwater that is found in their natural habit.

The tank should be checked regularly for having enough calcium in it, that is, at least 400 ppm, to help the coral grow its skeleton.

Who do hammer corals live with?

Though these LPS coral species are known to be aggressive towards other corals by attacking them with their tentacles, they can be seen living with unicellular algae in a symbiotic relationship. The coral provides the algae with shelter, the algae provide the coral with its bright colors, and both of them with food by performing photosynthesis.

Some species of small crabs or shrimps can sometimes also be found living in their tentacles.

In a reef aquarium setting, it has been found that the anchor corals do not attack most other Euphyllia corals except for the torch coral (Euphyllia glabrescens), which can harm the hammer coral with its tentacles instead.

Even butterflyfish should not be kept in the same aquarium, as they tend to nip on the soft tentacles of the hammers and can tear the polyps.

How long does a hammer coral live?

There is not much data available about the lifespan of the hammer coral (Euphyllia ancora), though it is estimated to be more than 10 years. The generation length of this species is thought to be 10 years, which is the average number of years between two consecutive generations of a species.

How do they reproduce?

The hammer corals can have both, sexual and asexual reproduction. In sexual reproduction, the male and female gametes from larvae when released into the water and subsequently, form polyps.

These polyps land on the substrate, where they will settle and start forming their skeleton made out of calcium carbonate. In asexual reproduction, a fragment can give rise to new polyps and tentacles, and eventually form a new colony.

The anchor corals can also grow in a tank by extending their polyps in either a branching formation or a wall formation. A branching hammer coral will grow several heads of the polyps in a branch-like formation, whereas a wall hammer coral will grow only one head that will keep on growing.

With a branching coral in a reef aquarium, it is also easier to cut one head of the polyps without harming the rest of it, while the same isn't possible with a wall coral.

What is their conservation status?

There are a lot of threats to the habitat of the hammer coral (Euphyllia coral), which is bound to have an impact on the populations of these corals as well.

Some of these reasons are climate change, rise in sea surface temperature, industrial pollution, human recreational activities, and tourism. There have also been huge outbreaks of the brown jelly disease in Euphyllia corals, which leads to tissue loss and is highly contagious across all species of corals.

These are some of the reasons why they have been categorized as Vulnerable by the IUCN Red List.

Hammer Coral Fun Facts

What do hammer corals look like?

The hammer corals have big, tubular, T-shaped, or anchor-shaped tentacles and polyps. They can be of a wide variety of colors, such as gold, green, purple, orange, gray, or neon green.

Their tentacles may or may not have a white or cream border to them. This species of corals can also have two colors in a single colony, giving your reef aquarium a most unique look!

It is essential to note that lighting plays an important role in the color of an anchor coral. Too much lighting can cause the polyps to expel the algae in its tissues that give it its color, which will lead to the coral losing its color and turning white.

If the light is too less, it may lead to the coral starving.

Thus, it needs a moderate amount of lighting to perform photosynthesis. The light should not come from metal halides directly as they are used to murky waters in their natural habitat.

How cute are they?

These corals can be justly considered one of the cutest corals found in the ocean because of their brightly colored, fleshy, anchor-shaped tentacles.

How do they communicate?

There is not sufficient information available about communication between corals. Some species are aggressive towards other corals, but the reason behind that is their need for survival. Thus, it is not clear whether hammers communicate with each other.

How big is a hammer coral?

It is not known exactly how big they can get in their natural habitat, but it is suspected that they can cover several square feet on a horizontal substrate in the ocean. In a tank or aquarium setting, the growth of hammers can be more than 3 ft (0.9 m) big.

Thus, in a tank, they would be about five times smaller than the biggest wels catfish.

How fast can a hammer coral move?

Coral species cannot move as they are immobile and stay in the same spot. Only their tentacles may move with the water movement or flow. The tentacles of hammer corals also move with the water flow in their natural habitat or in their tank or aquarium. This water flow should always be moderate.

How much does a hammer coral weigh?

The weight of hammers is unknown due to a lack of research.

What are the male and female names of the species?

The males and females of this species do not have different names.

What would you call a baby hammer coral?

There are no special names for a baby hammer coral. The closest thing to babies in this species can be the larvae that form after the male and female gametes are released. In asexual reproduction, it is a fragment that gives rise to a new colony of hammers.

What do they eat?

The hammer corals (Euphyllia ancora) are carnivorous and can depend on both, zooplankton and photosynthesis for their food, although they usually get by on just photosynthesis.

Thus, even in an aquarium, they don't need to be necessarily fed, just a moderate amount of lighting can be sufficient but evidence has shown that they are benefitted a lot if they are fed meaty marine food like krill, Mysis shrimp, and silverside fish.

Are they poisonous?

Hammer corals do have stinging cells on the tips of their tentacles, which can extend up to several inches and cause damage to other corals in their tank, but these are not strong enough to penetrate and harm the skin of humans beings, who have quite a thick epidermis layer.

They may, in some cases, cause rashes to your skin if you directly touch them.

Would they make a good pet?

These corals (Eyphyllia ancora) are sure to draw the attention of anyone with their presence in your tank. However, these corals are suitable for someone with previous experience with reef tanks, as they are neither very easy to take care of nor too difficult.

The water quality, lighting, water movement and flow, quantity of calcium in their tank need to be regularly checked and maintained.

Did you know...

Hammer corals are said to grow faster the more and better you feed them. That is probably why their growth rate varies in their natural habitat from the one when they are kept in tanks. In tanks, they are regularly fed with meaty food and kept in an environment that is healthy for them.

Hammer coral care

Taking care of a hammer coral (Euphyllia ancora) can be difficult for a beginner. Their light needs to be moderate to avoid coral bleaching or starvation.

The amount of calcium and alkalinity need to be within their required levels to allow the corals to grow their skeleton, which is made of calcium carbonate.

They need to be placed in a tank that can hold 30-50 gal (75.7-189.2 l). The flow of water needs to be not too much or too as it can harm the soft tentacles of these corals.

The hammers need to be placed at least 6 in (15 cm) away from other corals in their tank as they tend to be quite aggressive and sting them with their sweeper tentacles that can extend up to 10 in (25 cm).

These corals may not attack other Euphyllia corals except the torch coral. Sea anemone is also likely to harm the hammer corals and most other corals.

A branching hammer might be preferred to a wall hammer as their branches can be easily fragged in case of a problem, which is not possible in a wall hammer.

Before moving them to your aquarium, it is essential to check for diseases and infections like brown jelly, as they can harm the polyps and eventually kill the coral, leaving only the calcium skeleton base.

Do hammer corals sting?

Hammer corals can sting other corals and small prey to feed on them. However, their sting is not fatal to human beings and may only cause a rash-like condition if directly touched without protection.

Here at Kidadl, we have carefully created lots of interesting family-friendly animal facts for everyone to discover! Learn more about some other Anthozoa from our brain coral facts and fire coral facts for kids pages.

You can even occupy yourself at home by coloring in one of our free printable hammer coral coloring pages.