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What Do Hermit Crabs Need? (From Lighting to Shells)

What Do Hermit Crabs Need? (From Lighting to Shells)

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The purpose of this blog is to share general information and is written to the author's best knowledge. It is not intended to be used in place of veterinary advice. For health concerns, please seek proper veterinary care. In addition, as an Amazon Associate I earn from qualifying purchases.

Whether you won a hermit crab at a fair, or simply bought some to keep you company, you may now be wondering, “What do hermit crabs need?”

As a whole, hermit crabs have various caring aspects that need to be properly addressed. From tending to their nocturnal nature to their need for company, creating the right environment will ensure a healthier and longer life.

After all, hermit crabs can live as long as 15 to 20 years with proper care. In the wild, they can even survive for an incredible 30 to 40 years.

That said, stick around to learn more about what hermit crabs need to survive and thrive in their captive environment.

Do Hermit Crabs Need Heat?

As a tropical crustacean, you’ll want to accommodate this little fella by mimicking its natural habitat. That means high temperature and humidity levels.

Broadly speaking, hermit crabs need to live in an environment between 72 to 80 degrees F. Although hermit crabs can survive in lower temperatures, they wouldn’t be thriving as well.

That being said, temperatures dropping below 62 degrees F could potentially make your hermit crab more prone to stress and sickness.

On the other hand, temperatures exceeding 80 to 85 degrees F could also prove harmful.

Overheating can cause several symptoms ranging from a musty smell to diurnal activity. As nocturnal animals, this is considered abnormal.

Aside from that, hermit crabs do require heat, especially if their environment doesn’t meet their temperature requirements.

Do Hermit Crabs Need a Heat Lamp?

To keep your hermit crabs happy and healthy in a warm habitat, you’ll want to use tools like a heat lamp. The latter is a useful heat source for your hermit crabs, where it saves you from spending on underwater heaters.

Nevertheless, positioning the lamp is critical to your little crabs’ survival. Place it too close, then you’ll end up overheating them.

We recommend keeping at least a four-inch distance between the heat lamp and the tank. Otherwise, if the bulb comes too close, the glass roof may crack from the drastic temperature difference between the lamp and the water.

To avoid this, be sure to supply the area between the lamp and tank roof with some airflow. To make things easier, we suggest purchasing a tank thermometer to help you monitor the water temperature levels.

After a few nudges, you’ll find the optimal angle for your hermit crabs to comfortably bask in the heat rather than get cooked.

Do Hermit Crabs Need Water?

Of the 800 species of hermit crabs crawling around the globe, the majority of them are ocean dwellers. The other few are semi-terrestrial or more commonly identified as land hermit crabs.

Having said that, the cold-blooded crustacean does need water to survive. Your hermit crabs will use the water for various reasons such as bathing, drinking, and changing out their shell water.

Additionally, land hermit crabs store water in their tiny bodies to keep their gills well-hydrated.

Interestingly, these species have modified or reduced gills that can also act as lungs. Evolution certainly helped these little guys out.

That being so, hermit crabs adjust their breathing mechanisms according to their environment.

Consequently, they can neither fully breathe air as we do, nor can they truly breathe underwater. They merely require humid air for their survival.

Aside from that, hermit crabs do need water for their survival, but not just any kind of water. Both saltwater and freshwater sources are required.

How Much Water Do Hermit Crabs Need?

Since hermit crabs need two different water sources, namely fresh and saltwater, you’ll want to purchase a couple of small water bowls.

The bowls or trays should be deep enough for them to submerge their bodies in. Just be sure to find dishes that are easy for your hermit crab to move in and out of, otherwise, you’ll risk drowning it.

For this reason, you can purchase a few natural sea sponges to act as stairs for your hermit crabs to maneuver in and out. The sponges are also beneficial to keep around the tank to maintain high humidity levels of around 75% to 80%.

Do Hermit Crabs Need Saltwater?

Hermit crabs naturally reside in coastal regions giving them ample exposure to saltwater. Now, you don’t want to simply mix some regular table salt with tap water and call it a day.

Commercially sold salt usually contains traces of iodine which can be detrimental to your little crabs.

In addition to this, tap water consists of large portions of unknown minerals. When mixed with other compounds the solution can create harmful sodium and mineral levels

Instead, you’ll want to purchase distilled water and mix it with aquarium or oceanic salt. You can also opt for spring water.

Additionally, we recommend treating the mixture with water-conditioning fluid. That way, it’ll neutralize any traces of harmful chlorine.

Why Do Hermit Crabs Need Shells?

Have you ever seen a hermit crab without its shell? Well, it looks like a mix between a scorpion and a spider. Without its shell, you’ll notice the crustacean’s soft body, long tail, and hook-like legs.

Now, a shell-less hermit crab is vulnerable to several factors such as too much light exposure as well as threats from predators. In the latter’s case, you may notice a hermit crab hiding in its shell if you try to go near it.

Plus, the crawler needs the shell to store water so it can remain hydrated. Overall, hermit crabs need their shells for protection.

It’s basically carrying its home around, earning its initial name, hermit. Besides that, as the aquatic animal outgrows its shell, it goes out searching for a bigger one to accommodate its larger size.

Shell Origin

If you’re wondering where these shells come from, they’re originally owned by marine gastropods. That includes species like snails, clams, and other mollusk creatures.

Now, hermit crabs don’t just use any shell, instead, they assess its size, opening, and weight. After all, it’s practically considered home shopping for them as well since they live in the shell.

Do Hermit Crabs Need Light?

Even though hermit crabs are nocturnal creatures, they still need their share of light.

Circadian Rhythm Regulation

One of the reasons why a light source is critical to the little guys is that it regulates their circadian rhythm,

In other words, it helps them distinguish between night and day. For this reason, a little natural light exposure can make a world’s difference for them.

About 8 to 12 hours of daytime and 8 to 12 hours of nighttime should be enough for the crabs to regulate their biological clock.

Vitamin D Source

That being said, hermit crabs also need a light source to maintain a healthy dose of vitamin D. The light essentially integrates vitamin D into the crab’s skin.

Plus, it metabolizes the calcium in its system. A deficiency of vitamin D can lead to several health complications such as a poor immune system, soft female eggs, metabolic bone disorder, and even stunted growth.

Now, this doesn’t mean that you should shine a beacon onto their tanks. Hermit crabs have highly light-sensitive eyes.

Too much light can also cause disorientation and a lack of appetite. In turn, this could lead to serious unwanted complications.

Do Hermit Crabs Need Light at Night?

Thanks to their compound eyes, hermit crabs can see at night. Subsequently, they don’t need to be provided with a light source at night.

Their eyes consist of multiple tiny ommatidia, which are hexagonal-shaped units containing several photoreceptors. These are used to maximize the light input they get from their environment.

Along with their insect-like compound eyes, hermit crabs also use their antennae to navigate around the darkness. They have one short antenna responsible for sensing taste and smell, while the longer one detects objects or feels their surroundings.

Since hermit crabs are clearly armed with the right tools to handle a night crawl, they don’t need light when the sun goes down. Otherwise, a night light can mess up their circadian rhythm and do more harm than good.

Besides that, certain kinds of light can be less harsh and even mimic a nighttime environment for your hermits.

What Kind of Light Do Hermit Crabs Need?

Hermit crabs need light to distinguish their daytime from their nighttime. Luckily, you can find several light options available for your crabs.

Additionally, some of these options also double as heat sources.

White Light

If your hermit crab tank placement doesn’t have access to natural light, then you can use white light fixtures to mimic their daylight.

More specifically, UVB light can benefit the little crabs, especially for their vitamin synthesis. Besides that, you may also want to use light fixtures that come integrated with timers.

That way when nighttime rolls around the timer can automatically turn off the light. This is especially helpful if you have a busy lifestyle and may forget to turn the lights off.

Red Light

Apart from that, you may be able to use red infrared light during nighttime. Although hermit crabs can detect this light, it doesn’t cause them as much harm as bright white daylight.

Nevertheless, be sure to avoid purchasing party red lights. You’ll want to go for the same red light used for reptiles.

Blue Light

The purplish blue-hued light is originally made to produce partial light for reptiles. Nonetheless, you can use these moon or star lights for your hermit crabs.

These are an ideal solution if you’re looking for both a night light source as well as a heat source for the crabs.

What Kind of Sand Do Hermit Crabs Need?

Fortunately, hermit crabs aren’t too picky about their sand. You’ll mainly want fine grains so the crabs can burrow in them easily when their molting period comes around.

Playground Sand

For an affordable substrate, you can opt for commercially sold playground sand. Just be sure to sterilize it thoroughly by washing it and leaving it in the oven at 300 degrees F to dry off.

Calcium-Based Sand

Alternatively, you can use regular aquarium sand or colorful calcium-based sand, albeit, the latter may be a bit on the pricier end. Nevertheless, it does provide calcium-enriching benefits to keep your crabs healthy.

Coconut Fiber

In addition to playground sand and aquarium options, you can also use a more organic coconut fiber choice. As you may have guessed, this substrate is made of coconut husks.

The best part about this kind of substrate is that it can retain humidity levels in your hermit crab’s tank. You just need to keep the particles damp enough.

For a more soil-like texture, you can mix the coconut fibers with the regular sand. That being so, make sure to keep the sand layer about three to six inches above the tank floor.

Do Hermit Crabs Need Air?

Scoping out whether hermit crabs need air or not may be confusing given the fact that they have gills that can also act as lungs.

Generally, these crabs do need air, but it needs to be humid. Otherwise, dry air for long periods can end up suffocating the animal.

Apart from that, land and ocean hermit crabs may have slightly different needs. For the latter, they aren’t as fully capable as land crabs to stay out of water for too long.

In turn, most are kept in fish tanks since they spend most of their lives dwelling on ocean floors.

Meanwhile, land hermit crabs are more durable in terrestrial space and can survive outside of the water as long as the air is kept at 80% humidity.

They also still require water dishes to submerge their modified gills in.

Do Hermit Crabs Need Friends?

Despite what their name may suggest, hermit crabs aren’t built for solitude. In the wild, they flourish as large groups consisting of hundreds of members.

Hermit crabs can get lonely and do need friends. When you decide to purchase this crustacean, make sure to bring along a few tankmates to keep it company.

Apart from that, you’ll want to keep your eye out for any fighting since these crabs tend to get territorial. You may notice some pushing and antenna fights, in which case, make sure to separate them until they calm down.

Final Thoughts

What do hermit crabs need? Well, from adequate lighting to high tank temperatures, hermit crabs need a lot to survive.

Your main objective is to make sure their enclosure mirrors their wildlife. You’ll want to ensure they have access to saltwater, freshwater, a deep sandy floor, heat, and light.

In addition to this, try not to purchase one lone crab and instead get a pair for every five gallons in your tank.

Aside from that, hermit crabs are fascinating creatures to own, but remember to be mindful when purchasing them since they play a critical role in their ecosystem.

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