Hermit Crabs In The Ocean

Hermit Crabs In The Ocean

There are around 800 species of hermit crabs and are found in the ocean. The hermit crabs that are kept as pets are typically a species called “land hermit crabs“.

These do live near shorelines, however, they are not like other hermit crabs that can be considered marine hermit crabs. Marine hermit crabs live exclusively under the water and are sometimes kept as pets with reef tanks to help mimic their environment.

Hermit crabs that live in the ocean are often found in large groups because they are social creatures. They are referred to as Marine hermit crabs they prefer underwater living in shallow reefs or along beach shorelines, these ocean dwellers hardly ever leave the ocean to visit the land.

These two specific variations of hermit crab simply do better as a part of a group. It keeps them happy and healthy! While there are hermit crabs in the ocean, they aren’t necessarily the same as other crabs found in the ocean.

Even with around 800 species of hermit crabs roaming the ocean, the variations are truly vast. Hermit crabs are crustaceans, however, they aren’t technically a crab.

Hermit crabs are classified as decapod crustaceans, like other crabs, however, their body structure is what separates them from being a true crab.

Hermit crabs have a soft body under the shells they call home. The shells help protect them and when they outgrow the shells they have to find bigger shells to call home.

Hermit Crabs In Ocean

They Look For New Shells In The Ocean

Their shells shouldn’t be confused with other marine life such as sea snails. Snails create their shells from the excretions from their body. Hermit crabs do not produce their own shell, rather set up home in other sea creature’s shells.

The way that hermit crabs obtain their shells in the ocean is quite fascinating. Sometimes, they fight other hermit crabs for access to a shell which can result in death.

Fights can occur, but more often than not, they perform what’s called a “vacancy chain“. This process is a result of a hermit crab finding a shell that is entirely too large for its body. The shell has to be well-fitted to properly protect the hermit crab.

The vacancy chain starts with a hermit crab finding a shell that’s too large. They return back to their old shell and stake out the area where they found a larger shell.

The reasoning behind this is to seek out other shells from other marine life that might come along and take residence in the larger shell. Thus, the hermit crab can snatch up one of the left behind shells.

The bottom line is that a hermit crab will do whatever they can to obtain a new shell since it is the primary source of protecting it.

A major difference between aquatic hermit crabs and the land hermit crabs that are found along shorelines is that the aquatic hermit crabs can breathe strictly through their gills and do not have to store water in their shells to keep their gills hydrated.

In contrast, land hermit crabs do require water under their shell to keep themselves wet to prevent drying out. This is why hermit crabs need constant supplies of water when kept as pets.

Marine hermit crabs kept as pets need around 37 litres of water (or 10 gallons) since they require breathing underwater. Land hermit crabs on the other hand only need a bowl of freshwater and a bowl of saltwater in their tank to satisfy their need for water.

What Does A Hermit Crab Eat In The Ocean?

Hermit crabs in captivity can eat a variety of things such as vegetables, brine shrimp, etc. They are considered to be omnivores, meaning they eat both plant and animal matter.

Marine hermit crabs in the ocean tend to follow a similar diet. Hermit crabs, in general, aren’t very picky eaters. They’ve been known to eat a variety of things.

However, there are some key things that are a big part of their diet. Below are the foods that marine hermit crabs are known to eat in the ocean!

Foods Hermit Crabs Eat In The Ocean

  • Algae – Algae is a common thing found in the ocean that hermit crabs love munching on.
  • Small fish
  • Plankton
  • Worms
  • Kelp or seaweed

These foods are found right in the ocean alongside the hermit crabs and make for a delicious meal. They can scavenge for these foods quite easily in the water.

Moreover, the fish and plankton they consume are often snatched right up as they float by the hermit crab.

The land hermit crabs that are found along shorelines are known to eat similar things but more often are thought to eat things that wash up along the shorelines. This can include plant life, small marine creatures, etc.

Land hermit crabs in captivity should be fed a variety of foods to keep it interested. They can be known to get bored. This can include marine hermit crabs as well. Variety keeps them happy! Marine hermit crabs have no trouble finding a large selection in the ocean for food.

How Do You Find Hermit Crabs In The Ocean?

Aquatic hermit crabs can dwell in deep ocean beds and have been found in depths of up to 137 metres (or 450ft). While they can be found in deeper waters, aquatic hermit crabs and land hermit crabs will usually be found a bit closer to the surface and shorelines.

Specifically, the aquatic hermit crabs can be found in shallow reefs. They can be seen snorkelling in some parts of the world.

Hermit crabs that live in the ocean can be out of the water, but not for long. They simply need to be submerged in water and are unable to survive out of the water like the land hermit crabs.

In the ocean, aquatic hermit crabs will generally be found in structures left behind from corals, sponges, and even gastropods. These structures make great homes for the aquatic hermit crab as they provide sufficient shelter.

Moreover, it aids in their ability to catch floating food such as fish or small marine life.

When looking for land hermit crabs, they will always be near rocks that are intertidal. This means the rocks are exposed to water washing upon them and often will have algae living on them for the hermit crabs to eat.

It is much easier to locate a land hermit crab because they will always be near a shoreline where they have access to both land and ocean water. Waiting for the low tide gives the best access to seeing these creatures. They are generally under the rocks or on the rocks.

Can I Keep Hermit Crabs From The Beach?

It is possible to keep a hermit crab that is found at the beach. However. in some places of the world like Australia, it is always a good idea to check with the area where its found to ensure it isn’t illegal to take them.

Some areas of Australia can be protected parks where preservation is put into place. Otherwise, taking hermit crabs from the beach can be done.

Before keeping a hermit crab from the beach, it is important to be fully prepared for having a hermit crab at home. This includes having a proper tank, all the supplies it needs, and proper food.

Below are all the things to have ready for bringing home a hermit crab.

Items Needed For Hermit Crabs

39 to 76 litre (or 10 to 20 gallon) Tank

Tank size is really important. It helps to ensure that the hermit crabs have plenty of space to move around. If you’ve got an aquatic hermit crab, the tank size can be the same.

Water Source Of Fresh And Salt Water

If it’s a land crab from a beach shoreline, the water source only needs to be a bowl of freshwater and a bowl of saltwater. The bowls should be large enough for them to climb into but not be completely submerged.

If it’s an aquatic hermit crab, there should be enough water to submerge them. This keeps them in an environment close to their natural one.

It is important that the water be saltwater, as that’s the water they can survive in.

Never, ever use table salt as it contains iodine which is harmful to all hermit crabs. There are saltwater mixtures that can be bought to ensure the water is where it needs to be.

Climbing Items To Keep Them Entertained

Hermit crabs love to explore. Both land or aquatic crabs enjoy climbing items. These items should be safe for them to climb on, with no sharp edges and of materials they can hide under or climb on.

This could be driftwood, rope nets, cholla wood pieces (dried cactus) just to name a few. These items add variety to their tank and keep them entertained.

Use Substrate So They Can Burrow

The substrate is really important as hermit crabs need to burrow. Soft sand or coconut fibre are the two best substrates for hermit crabs.

Coconut fibre is especially good for land hermit crabs as they need humidity in their cage and it stays moist.

Once again, aquatic hermit crabs should have enough water to submerge themselves in, but it is okay to put sand in the bottom of their tanks.

Humidifier For Humidity Levels

Land hermit crabs require a humidifier to keep their tanks at the property humidity level. The humidity level should range anywhere from 70 to 80%.

Plenty of places online, as well as local pet stores, will carry a humidifier that will measure the humidity in the tank.

Spare Shells From The Oceans

Hermit crabs go through a molting period where they shed their shells. It is important and critical to providing a variety of different shells so that the hermit crab can find a new shell to carry on its best.

Moreover, when living in groups, hermit crabs should be separated during their molting so they aren’t disturbed. During this time, they might appear dead, but alas, they are just shedding their exoskeleton.

If they are burrowed under their substrate, they should be left there and not disturbed. If separating them is necessary, providing a substrate in the container they are put in is absolutely needed.

These are the biggest items needed to have a thriving and successful tank for a hermit crab. Once again, on top of having a well-maintained tank, it is also important to have a good variety of food choices for the hermit crab as well.

Land hermit crabs kept as pets have been known to eat small bits of cooked chicken that has been boiled in water as well as hermit crab food, lettuce, and other veggies.

Other foods can include shrimp, salmon, and even boiled eggs. Other veggies that are safe for hermit crabs include carrots and spinach.

They can also eat fruits such as mangoes and even coconut. All foods fed to a hermit crab should be cut up appropriately and be of the proper size for them to eat. Pieces too large won’t be able to be consumed properly.

While land and aquatic hermit crabs share some similar features and can be kept as pets, they have their overall differences. Either way, it is quite interesting to see how and where they actually come from.

The ocean and beaches are their natural habitats and when they’re kept as pets, it is critical to ensure that they have everything they need to keep them happy and healthy!

Hermit crabs are an interesting choice for a pet and can be quite fascinating to watch and care for. While most people might get their pet hermit crabs from a local pet shop, it can be beneficial to learn about where hermit crabs come from.

Considering they do need a water source, hermit crabs can be found in the ocean. Nearly all species of hermit crab are found in saltwater, although as pets they typically require a freshwater source as well.

Having both sources ensures the crab has access to water for drinking as well as storing it in their shell. Even though pet hermit crabs require access to both types of water, hermit crabs are found in the ocean itself.


Hello, my name is Mackenzie and I have created this website out of my love for all the world's beautiful creatures - great and small. I hope you find this website useful as I take you through various topics about a variety of some of our most loved animals and ways in which you can gain some knowledge on how to care for them properly.

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