If you intend to keep hermit crabs as pets, keep these social animals in sizable colonies. One way to make this interesting is to pair various hermit crab species in the same tank or aquarium.
You can’t pair land-based hermit crabs with marine hermit crabs. Terrestrial hermit crabs can’t breathe underwater, and marine hermit crabs can’t survive out of the water.
Different species of terrestrial hermit crabs can live together. Ensure that the habitat offers every hermit crab its territory and enough substrate for the largest hermit crabs.
Pairing different species of marine hermit crabs is trickier. Ensure that the hermit crabs have the same water hardness and temperature needs and co-exist with other aquarium favorites like fish.
Do Hermit Crabs Get Along with Other Hermit Crabs?
Hermit crabs are social animals that live in large colonies, usually in groups of 100 or larger. If you want to provide a happy life for pet hermit crabs, seek to replicate this by housing many of them together.
Mixing different species of hermit crabs is interesting for everyone. Marine hermit crabs, in particular, come in a wide array of colors, making for an eye-catching aesthetic in the aquarium.
Every hermit crab has its own personality, so there is always the risk of a cantankerous or combative hermit crab within the colony that rejects the company of others.
However, most hermit crabs take a “more the merrier” approach to living arrangements.
Two hermit crabs will usually get along okay, especially in a smaller tank, but around 4-5 is better. This many hermit crabs can peacefully co-exist in an aquarium of 10 gallons, though more space is better.
You can pair hermit crabs of the same or opposite sex and mix and match different species of hermit crabs. The only major concern is that you can’t pair marine and land-based hermit crabs.
Can You Mix Hermit Crabs?
Many different types of hermit crabs are available to be kept as pets. These will be terrestrial hermit crabs that live on dry land or marine hermit crabs that spend their lives underwater. Examples include:
| Terrestrial Hermit Crabs | Marine Hermit Crabs |
| Caribbean Hermit Crab (Coenobita clypeatus) | Dwarf Hermit Crab (Clibanarius sp) |
| Ecuadorian Hermit Crab (Coenobita compressus) | Polka Dot Hermit Crab (Phimochirus operculatus) |
| Strawberry Hermit Crab (Coenobita Perlatus) | Electric Orange Hermit Crab (Elassochirus gilli) |
| Cavipe Hermit Crab (Coenobita cavipes) | Halloween Hermit Crab (Ciliopagurus strigatus) |
| Rugosus Hermit Crab (Coenobita rugosus) | Scarlet Reef Hermit Crab (Paguristies cadenati) |
Different terrestrial hermit crabs can live together, as can various marine hermit crabs. If possible, have at least two of every species in a tank, so all the hermit crabs feel comfortable.
These two types of hermit crabs can’t interact. If you try to keep marine and terrestrial hermit crabs together, one of the varieties won’t survive.
Terrestrial hermit crabs rely on carbon dioxide and can’t breathe underwater. They can hold their breath and submerge in water for around 30 minutes but must emerge before drowning.
Marine hermit crabs are the opposite. They can’t breathe on dry land for long, relying upon oxygen found underwater. If these hermit crabs spend too much time outside the water, they’ll suffocate.
Introducing New Hermit Crabs to a Colony
If you keep hermit crabs as pets, you may wish to add more new playmates to an established colony. This is okay, but take a few steps to ensure all pets are happy with this arrangement.
Set up an isolation tank for the new hermit crab. Captive hermit crabs invariably begin their lives in the wild, and the transition into captive life leads to post-purchase syndrome (PPS).
Your new hermit crab will be extremely stressed for at least 2 weeks and should be kept alone while it adapts. The new arrival may also molt its exoskeleton upon arrival in your home.
Clean the main tank and introduce the new hermit crab to its tankmates. A clean tank will be considered neutral territory for all concerned, so existing residents and new arrivals will be equally accepting.
Considerations when Mixing Hermit Crabs
If you’re pairing multiple hermit crabs in the same tank, you’ll need to take these considerations under advisement to create a harmonious living environment:
Habitat Suitability
Pairing different species of terrestrial hermit crabs is simple in terms of living environment. All land-dwelling hermit crabs require a temperature of around 80OF and a humidity level of about 80%.
You may need to upgrade to a larger tank if you mix and match different terrestrial hermit crabs. As long as you provide enough food, heat, and hiding places, there are few other concerns.
Pairing different species of marine hermit crabs is more complicated. Ensure that all hermit crabs in your care flourish at the same water temperature and hardness and are compatible with any fish living in the same aquarium.
Size
Most concerns surrounding mixing species, especially terrestrial hermit crabs, boil down to size differences. Marine hermit crabs are usually smaller, though Dwarf hermit crabs are particularly tiny.
Land hermit crabs have more variety in mass and stature. In one critical sense, this is a good thing. Hermit crabs of disparate body shapes won’t come into conflict over shells.
Large hermit crabs will not fit into the shell of a smaller conspecific, so they won’t attempt to challenge a rival for a preferred shelter. Equally, a small hermit crab will show no interest in a large shell that’s too heavy to maneuver easily.
Ensure larger hermit crabs have their needs met. Bigger hermit crabs will have more voracious appetites than their smaller counterparts, so provide more food if you mix species. If you fail to satisfy a hermit crab’s appetite, it may cannibalize a small tankmate.
When setting up an enclosure for mixed-species hermit crabs, always work according to the largest animals in the tank. Provide enough substrate, robust climbing apparatus, and shade for these hermit crabs. Smaller hermit crabs will fall into line if they remain safe.
Temperament
Hermit crabs living in a colony arrange themselves into social hierarchies, with one hermit crab achieving ‘alpha’ status. Ethology confirms that hermit crabs recall their place in a hierarchy and respect this.
As a rule, the largest and most dominant hermit crab will become the head of a colony. This means that the larger of the former will become dominant if you pair two Purple Pinchers with two Ecuadorians.
This isn’t an exact science, and a smaller hermit crab may make a play for alpha status in a colony. In our above example, the largest Ecuadorian may consider itself equally worthy of this role. This can lead to conflict between your pets.
Monitor your hermit crabs carefully, ensuring they get along and remain safe. While most hermit crabs settle their differences amicably, those of different species may display unwelcome aggression that becomes dangerous.
Gender
You can pair mixed-sex hermit crab colonies of various species, as they rarely breed in captivity. Alas, this won’t necessarily stop males from trying.
When female hermit crabs are in season, they emit pheromones that attract male attention. Your male hermit crabs will rock the shell of these females, inviting them to mate. The majority of the time, these advances will be ignored.
This can grow tiresome for female hermit crabs, who will remain in their shells while the interested male is still roaming. It should also be noted that, as per Behavioral Ecology, larger males will show interest in smaller females.
Consequently, a large male hermit crab may take a shine to a smaller female of a different species. This male will then ‘guard’ this smaller female, not allowing other hermit crabs close to her and generating conflict with conspecifics.
This guarding behavior can arise in hermit crabs of the same species, so it’s not a concern exclusive to mixing different types of hermit crabs. All the same, it’s a consideration when pairing hermit crabs.
Different hermit crabs live together harmoniously in the wild and can also do so in captivity. A mixed species tank can work perfectly well if you meet their needs and keep marine and terrestrial hermit crabs apart.
