The secret of the relationship between sea anemone and hermit crab

In the plant and animal world, the phenomenon of symbiosis is often encountered - the living together of two organisms, in which each (or one of them) receives its own benefit. A striking example is the cohabitation of a hermit crab and an anemone: a coral polyp and a sea crayfish coexist peacefully and beneficially for each other in the depths of the sea.

The coral polyp and the sea crayfish coexist peacefully and beneficially for each other in the depths of the sea.

Cancer hermit

Hermit crabs belong to the family of decapods. Their abdomen is not covered with chitin, so most individuals settle in abandoned mollusk shells (hence the name). If there are no free “houses”, these arthropods drive the mollusks out of their shelters.

Bottle caps, corks, plant stems, and even Lego can also serve as shelter.

The size of crayfish does not exceed 3 centimeters. During evolution, the hind legs were shortened to make it easier to move with a shell on its back.

Content

The terrarium should be free and closed so that the crabs do not run away.
Pebbles or sand up to 12 cm thick should be poured onto the bottom, as these creatures love to dig holes and bury themselves in the sand. The terrarium should be cleaned once a week. It will be enough to change pebbles or sand once every six months. The hermit crab loves variety, so it is necessary to rearrange the decorations from time to time to make your pet as comfortable as possible. Crayfish do not require additional lighting. Don't forget about humidity! It should be 70-80% so that the crayfish do not die from drying out. It is very important to place empty shells at the bottom of the terrarium in case the hermit crab wants to change its house. If the temperature in the terrarium is below 18 degrees, it goes into hibernation.

Symbiosis

The relationships between organisms are different:

Amensalism is a relationship that causes harm to one organism, but does not in any way affect the second;
Parasitism is a symbiosis in which one individual uses another as a habitat;
Commensalism, which involves benefiting only one organism, while the other is indifferent;
Mutualism is a mutually beneficial cooperation between two species.

The symbiosis of a hermit crab and an anemone belongs to the latter type of relationship.

Content requirements

A comfortable stay for one hermit crab can be ensured with the help of an aquarium, the size of which is at least 40 liters. And more, depending on the size of the adult animal and the number of living organisms living in it. Water temperature is at least 26 degrees. A lower one will provoke diseases, and a high one will speed up metabolism too much and lead to premature aging. Acidity requirements: 8 pH. Salinity 35-37.

Hermit crab in an aquarium.

Place fine sea sand at the bottom of the aquarium in a layer of at least 12 cm. Other fillers can damage the delicate body of arthropods

It is important that the sand be sea sand, because any other sand will not be able to provide the ecosystem with the necessary minerals. In addition, hermits really like to climb and play

In this regard, the presence of natural pebbles and toys in their home is required. As the hermit grows, it will need a new home, so you should also add several shells of different sizes to the aquarium.

Neighborhood

It happens that crayfish, while looking for a home, offer their relatives to exchange shells. They tap their claws on the neighbor's house. If the proposed exchange suits the latter, then the crayfish exchange shells. Otherwise, they diverge or enter into confrontation, you never know.

Hermit crabs do not tolerate loneliness at all (despite their name). For this reason, there should be two or more individuals in the aquarium. Practice shows that representatives kept in captivity are very calm. It is very rare to see them aggressive.

But snails have almost no chance of surviving with such neighbors. The shells will be appropriated and their previous owners eaten.

In most cases, the hermit coexists peacefully with fish and shrimp.

However, there is a creature whose proximity brings benefits to cancer - sea anemone. The symbiosis of the hermit and sea anemone is fascinating! He carries her on his shell and feeds her, and she protects him with poisonous tentacles!

A hermit, moving to a new house, carefully takes his neighbor with him!

Nutrition

Feeding arthropods rarely causes problems. This is due to the fact that these animals eat any kind of food. They are scavengers; in most cases, the remains of fish food falling to the bottom are sufficient. If you want to pamper your pet, offer him seafood: shrimp, squid, octopus, dry seaweed. Food must be pre-chopped. In addition to collecting “edible” garbage, the hermit rids the aquarium of detritus, lower algae and cyanobacteria.

Hermits are very smart animals. They quickly find their bearings when feeding other inhabitants of the aquarium (for example, fish). At the right moment, the crayfish will be in the feeding area to pick up the leftovers.

Protection

One crayfish takes one or more sea anemones, which protect it in times of danger. Marine polyps have stinging cells (nematocytes) that can kill or paralyze their prey. When an enemy attacks, the polyp spreads poisonous tentacles over the cancer, increasing the chances of salvation. Anemones even scare away octopuses and crabs from themselves and their partner. In humans, touching an anemone causes a burn .

Description of sea anemone

Sea anemone (sea anemone) is an animal from the class of coral polyps, has a cylindrical body with tentacles at the end (the tentacles are located in several rows around the mouth opening). The tentacles have stinging cells - with their help, the sea anemone paralyzes small sea animals. The anemone grabs immobilized prey with its tentacles and pulls it into the mouth. The poison that the stinging cells secrete causes severe burns to human skin, so it is better not to come into contact with sea anemones.

The lifestyle of sea anemones is sedentary; they can move at a speed of 8 cm per hour, but most often they attach to some surface (stones, soil).

The anemone does not have a hard skeleton, and due to its low speed of movement, it can be left without a sufficient amount of food. Therefore, you can often observe a symbiosis between an anemone and a hermit crab - such a union provides advantages not only to the polyp, but also to the crustacean.

Food and movement

For sea anemones, this relationship is beneficial in terms of nutrition and mobility. The anemone moves independently only in rare cases, so it uses the hermit crab as a vehicle. Traveling with the crayfish, she feasts on the remains of his food. Along the way, the sea anemone itself hunts for fry, eggs and plankton. The hermit provides the sea anemone with freedom of movement, thanks to which it encounters prey more often.

Sometimes the crayfish feeds on food caught by the stinging cells of the sea anemone. Thanks to this, he develops immunity to poison.

Interesting Facts

Interesting Facts:

Instead of a shell, a hermit crab can use hollow objects - lids, parts of bottles, cups, glasses.
Some types of crustaceans do not live in shells.
If, when danger arises, an individual hangs from its shell, it means that it will soon die. A healthy animal will first hide in the house, and then begin to poke its eyes and antennae out of it.
Cancer has good hearing; sharp sounds can frighten him.
Determining whether a pet has died is easy. A living arthropod will offer resistance when any of its limbs are flexed.
To breathe, the crustacean uses gills, extracting dissolved oxygen from the water.

Hermit crabs are a useful decoration for an aquarium: they will bring pleasure to their owners and clean the artificial pond of cyanobacteria and detritus.

Next CrustaceansShrimp red crystal. A young popular species for experienced aquarists

Special relationship

When a cancer grows out of its shelter, it looks for something new. Further, the behavior of cancer depends on its type. Pagurus prideaux carefully separates the sea anemone from the old base and transfers it to the new shell. The sea anemone does not resist, as “one of its own” unhooks it. If for some reason the partner does not like the new shell, Cancer will look further. Only after her approval, the cancer fills the shell, and the sea anemone is attached to the top.

Pagurus prideaux with its sea anemone.

The sea anemone Adamsia palliata can exist without symbiosis for only a couple of months . Adult organisms always interact with hermit crabs.

Pagurus excavatus choose a shelter with an anemone already attached. When the crayfish grows up, it leaves the shell along with the anemone and goes on a new search.

There are cases when the sea anemone is attached directly to the shell, protecting vulnerable spots. Anemones also settle on one claw, covering the entrance to the shell, or on both limbs, acting as a weapon.

In symbiosis with the hermit crab, the sea anemone quickly increases in size. The boundaries of its sole extend throughout the shell, especially if several organisms are attached to the marine arthropod. They are distributed evenly over the area so as not to knock over the roommate. Representatives of the species Adamsia palliata secrete a hardening chitinous mass, increasing the size of their shell. This allows the hermit crab and sea anemone not to look for a new home for a long time.

In rare cases, a hermit crab, unable to find food for itself, begins to attack “its” sea anemone.

Could there be a third partner?

There are cases when the company of crayfish and sea anemone is supplemented by a polychaete worm. The worm settles inside the shell. It is interesting that other worms of the same genus are eaten by cancer. The selected cohabitant remains untouched and is transferred when moving to a new shell along with the sea anemone.

The worm performs the function of a kind of orderly. It feeds on the leftover food of the crayfish and parasites located on the abdomen.

Sometimes the third cohabitant becomes a polychaete worm, which settles inside the shell

Shedding

As mentioned above, a durable chitinous shell reliably protects the crayfish from the sharp teeth of the enemy, but on the other hand, it restrains its growth. However, nature has taken care of solving this problem, and it has the ability to periodically completely shed its old shell. Not only the chitinous coating of the cancer is renewed, but also the upper layer of the retina and gills, and part of the digestive tract.

In young crustaceans, already in the first summer, the shell changes up to 7 times; with age, the number of molts decreases and an adult gets by with one molt per season. The shell change occurs only in the summer, when the water in the lake or river warms up.

You should not think that this process of “rebirth” is easy and quick. It can last from a few minutes to a day. The arthropod first frees its claws with great difficulty, then the rest of its legs. Often, when molting, limbs or antennae break off, and the cancer lives for some time without them. Over time, the lost parts grow back, but have a different appearance. Therefore, crayfish fishermen often catch animals with claws of different sizes; one of them may have an ugly or underdeveloped shape.

Under the old “skin” before molting, a new soft cover has already formed until it hardens, and this will take about a month, sometimes more, the arthropod grows in length and is an ideal food for predatory fish and its larger relatives. And since he molts not in a shelter, but in an open space, he needs to get unharmed to his place of residence, where he sits out for up to 2 weeks without food, and waits until the cover more or less becomes keratinized.

Popular types

There are hundreds of varieties of hermit crabs known. By and large, they differ only in color, less often in size. Among aquarium lovers who choose arthropods by color, the following representatives are considered the most popular.

Hermit crabs: blue-striped, golden-spotted, orange-striped, red-legged.

In the wild

Local residents and tourists often encounter the following crayfish on the coast. These freedom-loving arthropods are not suitable for aquarium keeping, but you must enjoy their beauty!

Diogenes

Can be found on the coast of Anapa. It is small in size - about 3 cm. Body color is pink or grayish. The legs, eyes, antennae of the organs of smell and touch extend beyond the shell.

Clibanarium

Inhabits rocky terrain. Usually lives in the voluminous shells of rapans. They differ in orange, red (the color of coral reefs) color.

Palm thief

Uses shells only at the beginning of life. Adults reach a length of 40 cm, body weight - about 4 kg. Their meat is used for cooking. Crayfish live on land on the islands of the Indian Ocean.

Symbiosis of hermit crab and sea anemone: mutually beneficial coexistence