The Ecuadorian hermit crab (Coenobita compressus) is one of the smallest terrestrial hermit crabs that are commonly kept as pets.
The Ecuadorian hermit crabs have specific requirements for temperature, humidity, diet, and maintenance. Based on this, I would say that these hermit crabs are not for beginners.
If you are thinking about housing these hermit crabs or simply want to know more about this species, you have come to the right place.
In this article, I have gathered all information about Coenobita compressus. It covers all aspects, from natural habitat conditions and how Ecuadorian hermit сrabs should be cared, to dietary requirements and behavior aspects.
Quick Notes about Coenobita Compressus
| Name | Ecuadorian hermit crabs |
| Other Names |
Pacific hermit crab, E-crab, Eqqie, or Eccies |
| Scientific Name | Coenobita compressus |
| Type | Terrestrial |
| Tank size (minimum) | 10 gallons (~40 liters) |
| Keeping | Moderate |
| Breeding | Very Difficult |
| Average size (carapace length) | up to 0.8 inches (1.8 cm) in length |
| Optimal Temperature | 78 – 88°F (26 – 31°C) |
| Water type | Freshwater and saltwater bowls |
| Humidity | >70 % |
| Substrate | Mixture of cocofiber and sand |
| Diet | Detritivore /omnivore |
| Temperament | Peaceful. Social |
| Life span | up to 15 years |
| Color Form | From blue-green to gray-brown |
Distribution of Coenobita Compressus
The Ecuadorian hermit crab is indigenous to the Pacific side of Central and South America (from Lower California to Chile).
They can be found in Perú, Ecuador, Chile, Colombia, Panamá, Costa Rica, El Salvador, and México.
Natuarl Habitat of Coenobita Compressus
Coenobita compressus live on the Pacific seashore (rarely more than 330 yds (300 meters) inland).
They are frequently found both in sandy areas (like beaches and dunes), and tropical (in the grass and rainforest areas) under the rocks above high tide.
Description of Coenobita Compressus
Coenobita compressus is a very small terrestrial hermit crab. It was recorded that the largest male had a cephalothorax length of 1.5 inches (3.8 cm) while the largest female had a cephalothorax length of 1.1 inches (2.8 cm).
On average, though, the carapace usually ranges from 0.5 to 0.8 inches (1.2 – 1.8 cm) in length. It makes them the smallest pet land hermit crabs from the genus Coenobita.
Like most hermit crabs species, Coenobita compressus does not have complete exoskeletons and uses gastropod shells to protect its soft abdomen. These hermit crabs use chelae as lids for blocking their shells.
Distinguishing characteristics of Coenobita compressus:
- Carapace. The carapace can range from mottled light to dark brown.
- Color. These hermit crabs exhibit considerable variability in color. Young individuals may range from blue-green to gray-brown and their coloration is generally uniform.
Adults may also vary from a very pale gray, to almost black, to brown. In adults, the coloration may be either uniform or have considerable contrast.
- Eyestalks. The eyestalks are compressed and are generally brown dorsally, white laterally, and ventrally.
- Eyes. Compared to the round eyes of other Caribbean hermit crab species, the eyes are more oval-shaped and thicker.
- Antennae and Antennules. Dark brown. There is a black diagonal stripe behind the base of the antennae.
- Chelipeds. Chelipeds are medium brown to brownish-orange with some light brown tubercles. Their big claw has 4 or 5 small ridges on the upper part.
- Walking legs. The tips of the second pair of walking legs are darker compared to the rest of the legs. The 2nd and 3rd walking legs have light and dark brown granules.
Lifespan of Coenobita Compressus
These crabs have been known to live for over 30 years.
However, in captivity, Ecuadorian hermit crabs usually do not live that much. Even under optimal conditions, they usually live up to 10 – 15 years.
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Typical Behavior of Coenobita Compressus
Ecuadorian hermit crabs are most active at night. Activity generally begins in the evening shortly before sunset. However, in humid vegetated areas and in captivity many hermit crabs stay active even during the day.
Ecuadorian hermit crabs are very social animals. In their natural environment, they interact with each other, forming large colonies that also help them to exchange shells according to their needs.
This is a very active hermit crab species. In addition, they are extremely quick. Although, there is considerable variation in speed even among hermit crabs of the same size. It was recorded that some individuals may crawl up to 0.25 mph (0.4 km/h).
These crabs have lots of personalities and their behavior also greatly depends on the individuals. Some of them can be shy and prefer to retreat to their hiding places when disturbed whereas some Ecuadorian hermit crabs may be very outgoing or even aggressive.
Coenobita compressus is a burrowing species. In the wild, they burrow to rest, protect against predators, and dehydration. They dig a lot and dig deep. Actually, it can be a problem for small tanks with multiple hermit crabs because they may easily dig up other crabs.
Surprisingly, these hermit crabs are also very good climbers. In Latin America, they are also called Cangrejos de árbol or Tree crabs
Features:
- Social: Yes
- Active: Yes
- Peaceful: Yes
- Burrowers: Yes
Diet of Coenobita Compressus
These hermit crabs are considered to be generalist scavengers, eating
plant and animal material washed into intertidal and supratidal areas (such as dead animals, feces, leaves, fruits of mangroves, coconuts, and other plants).
Like with other Coenobitu species, negative preference induction has been also observed in Coenobita compressus. It means that hermit crabs chose items not included in their maintenance diet more frequently than expected by a random model of diet choice. In other words, they prefer foods that they have not recently eaten.
Results of the experiments showed that when Ecuadorian hermit crabs were exposed to one food for at least 9 hours preferred foods having other odors for the next 6 hours.
Interesting fact: Coenobita compressus has been shown to detect odors from a distance of at least 16 ft (5 meters).
General recommendations:
The food provided should be approximately 20% meat-based diets and 80% vegetables.
In captivity, Ecuadorian hermit crabs can be very picky eaters and it is only one of the problems when keeping them.
It is not uncommon when they refuse to eat for a few days if something does not suit them. That is why it is highly recommended to change their diet regularly. A multiple-item diet provides higher relative growth rates than crabs fed single-item diets.
Hermit crab keepers also noticed that this species tend to enjoy protein-rich food more than other hermit crab species. Thus, protein should be always on the menu.
| They also require nutrients like calcium, astaxanthin, carotene, and even antioxidants, to be healthy.
Important: Avoid or be very careful with spicy, sour, fatty, salty, sweets, and food from the table. For example, foods high in oxalic acid also impede the absorption of calcium by binding the mineral. |
In captivity, Coenobita compressus will consume foods like:
- corns,
- carrots (these supply the carotene also needed to maintain their color),
- leafy vegetables,
- oak leaves,
- spinach,
- tree barks,
- nuts and seeds,
- bananas,
- cranberries
- broccoli,
- sweet potatoes,
- red peppers,
- pumpkin,
- squash,
- dead snails, crickets, (and other insects).
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How Often to Feed Coenobita Compressus
Adults can be fed 3 – 4 times a week whereas juveniles should be fed daily.
- Leave their food in there for 24 hours before removing it (including fruits and vegetables).
Note: Make sure that whatever they do not consume in one day is removed to prevent moles. - Coenobita compressus can be pretty aggressive eaters. It is very important to not let them starve or deprive them of any food, there is a risk that they can try to go after their tank mates (cannibalize).
Keeping and Housing Coenobita Compressus
The quality of hermit crabitat is always the main reason why our pets have a reduced lifespan. Bad crabitat will lead to stress, pathogens, and injuries. As a result, these factors will significantly reduce their lifespan and survival rate in general.
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Tank Size (Enclosure):
Do not look at their size. Ecuadorian hermit crabs are very active animals and need a lot of space to move in the tank.
A 10-gallon (40 liters) tank is recommended minimum for one small Coenobita compressus. For a pair of crabs, you will need a 20-gallon (80 liters) tank or even more.
| Important:
Remember, Ecuadorian hermit crabs dig a lot! Thus, having a larger tank is always preferable because it can be easier to make diverse areas for them to hide. Having a smaller tank will significantly limit their freedom. It will stress and make them more aggressive toward each other. |
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Water:
Coenobita compressus adapted to live near the seashore. Therefore, in captivity, they need constant access to seawater to maintain gill moisture. They will die without access to fresh and seawater.
Note: Hermit crabs have a very low resistance to water loss. So, they fill their shell with sea and fresh water inside of the shell for both ionic and temperature balance.
In the crabitat, the presence of both freshwater and saltwater is absolutely crucial to create a favorable environment for this species.
Provide them with:
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You do not have to make huge pools.
Generally, the water only needs to be a few inches deep to completely submerge your Ecuadorian hermit crab with a safe way to exit (for example, pebbles, a plastic mesh, etc.).
How to prepare saltwater:
To prepare saltwater you can use Instant ocean marine salt (or similar products – check the price on Amazon). This is a great choice. It is pretty cheap and will last a very long time. Follow the manufacturer’s instructions to avoid mistakes.
Important: Do not ever use simple aquarium salt or table salt!
How to prepare freshwater:
Provide Coenobita compressus with something like bottled spring water.
Note: Distilled water is not the best option due to a lack of minerals in it.
If you decide to use tap water, let it age for 24 hours before using it. Tap water contains chlorine and it is toxic to for hermit crabs. In addition, chlorine slowly destroys the shell structure.
Instead of waiting for 24 hours, you can also use a water conditioner. For example, Seachem Prime will remove also toxic gases, and bind to heavy metals, any ammonia, nitrites, or nitrates present for up to 48 hours.
Important:
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Temperature:
The temperature inside the enclosure should always be between 78 – 88°F (26 – 31°C). Coenobita compressus does love warm temperatures. Even under slightly lower temperatures, these hermit crabs become sluggish and slow.
Note: Hermit crabs are cold-blooded animals. Their body temperature varies with the temperature of the environment.
Use a quality tank heater or clamp lamp to maintain temperature.
In addition, I also definitely recommend a thermostat. It will protect your hermit crabs from overheating or getting too cold.
| Warning: Heaters should never be placed under the crabitat because they can overheat your substrate and burn or kill molting hermit crabs there. |
The best (safest) option will be to put the heater to the side of the tank, ideally, partially above the substrate line to heat the air as well.
Humidity:
Hermit crabs need humid air to breathe properly. Thus, an ideal range is considered to be between 70 and 90 %.
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Substrate:
Ecuadorian hermit crabs are very active diggers. They burrow to hide, rest, and protect themselves when they are molting.
Burrowing is natural for them and it stresses them a lot if they cannot do that.
Therefore, we need to simulate this behavior by providing a deep moist substrate.
| These hermit crabs should have at least 6 – 8 inches (15 – 20 cm) deep substrate. If your setup allows it will be better to go even for the deeper substrate. |
The moist substrate has two functions:
- Maintains humidity level.
- Allows hermit crabs to dig underground and form a cave without collapsing.
The substrate should hold its shape when you squeeze it (so-called “sandcastle consistency”). However, not so wet that it drips or pools water.
| Important: Make sure not to waterlog the substrate to avoid the buildup of mold and other parasites. |
Tip: There is a simple trick to test the consistency. Take a pencil and stick it down and pull it back up. If the tunnel doesn’t collapse, your substrate is good enough.
The substrate may also require maintenance such as spraying with fresh dechlorinated water on a regular basis to keep it moist enough since the moisture in it will evaporate over time.
Some popular choices of the substrate include:
- coco fiber (Eco earth),
- peat moss,
- organic topsoil,
- Jungle mix soil,
- Zoo Meds Creatures Creature soil,
- Reptisoil,
- The Bio Dude Terra.
It is also possible to use a combination of different substrates, for example:
- coco fiber and sand and (5:1 ratio). It is easy to maintain and it holds moisture very well.
- a mixture of peat moss and organic topsoil (1:1 ratio).
| Do not use only sand! Sand often becomes supersaturated even though the top couple of inches are completely dry. If you decide to use sand, do it only in combination with other substrates. |
How to Prepare Sand
- Place it into a bucket and spray the sand with a hose.
- The excess water will run out of the bucket and the water will be cloudy and dirty initially.
- Keep rinsing. You will notice that the water will run clearer.
- If you think that sand is clean enough – rinse it again for a few more minutes!
Important:
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Lighting:
There are no special requirements.
Ecuadorian hermit crabs are nocturnal animals. Basically, using ambient light is enough.
Hiding places (Decorations):
The main purpose of incorporating decors in a tank is to replicate its natural habitat and provide the best environment for the hermit crabs. Ecuadorian hermit crabs enjoy hiding, burrowing, and climbing.
Shelter and protection are key requirements for any crabitat, especially, if you decide to keep them in a community tank.
You can use all types of leaves, wood, plants, PVC pipes, alder cones, and other decorations to enrich their environment.
Important: Make sure that the décor is safe as well. For example, avoid using rocks, ceramics, etc. because hermit crabs can damage themselves if they fall.
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Shell preference (Shell shop):
All hermit crabs are critically dependent upon gastropod shells for their survival and reproductive fitness and Coenobita compressus is not an exception.
Given the scarcity of shells, fighting for them is a common occurrence.
Nonetheless, many studies and experiments have also shown that different species of hermit crabs will exhibit different preferences for shells and suitable opening sizes (with D-shaped openings).
It was observed that Ecuadorian hermit crabs preferred Nerita scabricosta over other shell species. This is probably because Nerita scabricosta is one of the lightest species of shell, it also has a very high internal volume/weight ratio.
Interesting fact: Do you know that shells are very costly to carry? The use of a shell by a terrestrial hermit crab represents a 50% increase in oxygen consumption relative to a crab without a shell.
The list of shells preferred by Coenobita compressus includes:
- Nerita scabricosta
- Cerithium browni
- Turbo saxosus
- Turbo fluctuosus
- Thais biserialis
- Thais speciose
- Thais melons
- Nerita funiculate
- Nerita melanotragus
- Zebra littorina
- Tonna spp.
- Tun spp.
Warning: Do not use glass shells. First, these shells are very heavy for hermit crabs. Second, they do not provide enough secrecy. In transparent shells, they cannot hide and it stresses them out even more.
| Important: provide them with lots of shells to choose from. The “Shell shop” should contain shells of different shapes and sizes. It is recommended to have at least 5 shells per hermit crab, but more is always better. |
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Cleaning:
Keeping crabitat cleanliness is important. Remove their feces and food crumbs as often as you can. It will increase their survival rate.
Direct and prolonged contact with its waste and leftovers may lead to dangerous pathogenic agents infecting the organism.
Handling and Bathing Coenobita Compressus
You need to handle your hermit crabs with utmost care. They are not pets you can play with.
Do not take them out just because you want to. You should really handle him as little as possible. They stress very easily.
Be cautious too, they can snap at your fingers with their pincers. Generally, it does not hurt BUT you can flick your hand instinctively and your pet will go flying somewhere. They can get hurt easily, even with their hard shells.
Despite popular practice, it is not recommended to bathe Coenobita compressus as well.
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Main Care Rules of Coenobita Compressus:
- Keep the environment humid consistently. The humidity levels should be regulated to 70 – 90 %, monitor this with a humidity gauge or hygrometer.
- The substrate should be kept damp (‘sandcastle consistency’). Check it daily.
- Provide as many décors as you can!
- Eliminate chlorine and contaminants from the freshwater before usage.
- Replace the water at least once every 2 – 3 days.
- Clean their water bowls and enclosure.
- Don’t keep only one crab. They are highly social.
- Provide various food items to diversify their diet.
- Remove leftovers daily to avoid mold growth.
- Provide deep substrate.
- Replace the substrate bedding at least once every 6 – 8 weeks with a fresh one.
- Hermit crabs’ health needs to be maintained by separating them from specks of dirt, such as food and metabolic waste (feces and urine).
- Make sure the lid of the tank is closed tightly so that they cannot escape it.
- When they are under the substrate, do not dig them up unless you absolutely have to!
Coenobita Compressus and Molting Cycle
In order to grow, Coenobita compressus will shed its exoskeleton in a process called molting. It also allows them to restore lost limbs.
In nature, hermit crabs usually shed their old shell and harden their new ones within the burrow to increase its chances of surviving the vulnerable soft-shell stage. Recently molted hermit crabs are soft and also may desiccate very fast.
Molting hermit crabs should be disturbed only in emergency situations.
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Breeding Coenobita Compressus
The reproductive traits of Coenobita compressus haven’t been fully described in the scientific literature (at least I could not find any at the moment of writing this guide).
Thus, breeding these hermit crabs is extremely difficult in home conditions. I believe there are only a few people who managed to do that.
| Ecuadorian hermit crabs are all wild-caught. So, instead of supporting the pet industry, you can try to adopt them rather than purchase them. |
The main problem is that terrestrial hermit crabs (Coenobita spp.) undergo larval development in the sea and then move to land as a megalopa, where it metamorphoses and stays for the rest of its life.
Sexing:
Ecuadorian hermit crabs are characterized by sexual dimorphism.
In males, coxae of the 5th legs of both sides are produced ventrally, unequal coxa, and the right side is produced into an elongate tube, generally longer than the left one; the right tube is turned towards the left and curved ventrally.
Mating:
Males detect females with the antennules and are able to distinguish receptive over unreceptive females. This suggests that females are consistently releasing information (pheromones) about their status into the environment.
Eggs:
Currently, there is no available data on the number of eggs females can carry. Presumably, females can carry several thousand eggs.
Females carry the eggs for about a month. They are hidden in the shell.
Hatching:
The complete larval development of Coenobita compressus is described and illustrated based on larvae reared in the laboratory.
This species has 5 zoeal (larvae) stages. The zoea-egg hatches out almost immediately at a stimulus exerted by seawater, and the zoea becomes free. It generally swims in a heads-down position.
| # | Total length (mm) min/max |
Duration (days) |
| Stage 1 | 3.0 – 3.1. | 5 – 6 |
| Stage 2 | 3.3 – 4.1. | 4 – 9 |
| Stage 3 | 4.5 – 5.0 | 1 – 8 |
| Stage 4 | 4.4 – 5.2 | 3 – 10 |
| Stage 5 | 5.5 – 5.9 | 6 – 10 |
| Megalopal stage (glaucothoes) |
4.1 – 4.6 | 27 – 32 |
They bury themselves in damp sand approximately 29 days after metamorphosis and emerge as young crabs 1–5 days later.
Experiments showed that around 70-80% of the zoeae can reach the megalopal stage. About 10% survive to the first crab stage.
Coenobita Compressus and Suitable Tankmates
Ecuadorian hermit crabs are very social animals. In the wild, they are found in huge groups. Therefore, they should never be kept alone.
The lack of social need will stress them a lot and shortens their lifespan.
At the same time, because of their small size, it is recommended to keep them with the conspecifics. Larger hermit crab species may bully them.
In Conclusion
Ecuadorian hermit crabs are cute, active, and simply gorgeous animals!
Nonetheless, they are not for beginners. So, if you are new to this hobby, please, resist an impulse buy.
This species has very specific conditions to be met for its diet and habitat. You should only acquire them if you are willing to give them the special care and attention they need.
References:
- Abrams, Peter. “Shell selection and utilization in a terrestrial hermit crab, Coenobita compressus (H. Milne Edwards).” Oecologia2 (1978): 239-253.
- José-Luis Osorno, Lourdes Fernández-Casillas, Cristina Rodrı́guez-Juárez, Are hermit crabs looking for light and large shells?: evidence from natural and field induced shell exchanges, Journal of Experimental Marine Biology and Ecology, Volume 222, Issues 1–2, 1998, Pages 163-173.
- Ball, Eldon E. “Observations on the biology of the hermit crab, Coenobita compressus H. Milne Edwards (Decapoda; Anomura) on the west coast of the Americas.” Revista de biología tropical2 (1972): 265-273.
- Herreid, Clyde F., and Robert J. Full. “Locomotion of hermit crabs (Coenobita compressus) on beach and treadmill.” Journal of Experimental Biology1 (1986): 283-296.
- Brodie, Renae J. “Ontogeny of shell-related behaviors and transition to land in the terrestrial hermit crab Coenobita compressus H. Milne Edwards.” Journal of Experimental Marine Biology and Ecology1 (1999): 67-80.
- Thacker, Robert W. “Food choices of land hermit crabs (Coenobita compressus H. Milne Edwards) depend on past experience.” Journal of Experimental Marine Biology and Ecology2 (1996): 179-191.
- Brodie, Renae, and Alan W. Harvey. “Larval development of the land hermit crab Coenobita compressus H. Milne Edwards reared in the laboratory.” Journal of Crustacean Biology3 (2001): 715-732.
- THACKER, ROBERT W. “Avoidance of recently eaten foods by land hermit crabs, Coenobita compressus.” Animal Behaviour2 (1998): 485-496.
- Contreras-Garduño, Jorge, José Luis Osorno, and Alex Córdoba-Aguilar. “Male-male competition and female behavior as determinants of male mating success in the semi-terrestrial hermit crab Coenobita compressus (H. Milne Edwards).” Journal of Crustacean Biology3 (2007): 411-416.
- Guillén, Fedro Carlos, and José Luis Osorno. “Elección de concha en Coenobita compressus (Decapoda: Coenobitidae).” Revista de biología tropical(1993): 65-72.
- Bright, Donald B. “The land crabs of Costa Rica.” Revista de Biología Tropical2 (1966): 183-203.