Hermit crabs are one of the most fun little critters you can bring home and keep as a new pet. They’re feisty and interesting and add some color and uniqueness to any home environment.

Read below for some helpful tips for hermit crab care, nutrition, setting up their habitats, and how to handle these little guys with proper care.

Quick Intro to Hermit Crabs

Family: Paguridae and Coenobitidae
Scientific Name: Paguroidea
Other Names: N/A
Care Level: Easy to difficult, depending on species

Natural Habitat, Identification, and Where to Buy

There are several different species of land hermit crabs. They originate from tropical areas of the Western Caribbean, the Indo-Pacific region, and the Western Atlantic.

This species of crab lives close to the shoreline and needs access to both water and land. They make use of pools and crevices of seawater to stay moist and dampen the interiors of their shells. They mate and spend the early parts of their lifecycles in the water. Some crab species are entirely aquatic.

Purchasing hermit crabs are easy and are located at a wide range of pet stores and online.

Tank Setup

Minimum Tank Size:10 gallon tank
Optimal Tank Size: 15+ gallon tank
Optimal Tank Shape:A standard shaped aquarium tank is acceptable.
Recommended Filter Type: Hermit crabs do not a filter for their water in the aquarium, instead their water bowls should be routinely changed, using pure, filtered water.

The optimum tank temperature needs to remain between 75 85 degrees Fahrenheit during daytime and 65-75F. To ensure your aquarium remains between acceptable temperatures it is important to use a thermometer.

Hermit crabs are tropical and do best with high humidity. If your crabs do not have enough humidity they will have breathing difficulties. Ideally, this humidity should be between 70-80%. This can be achieved by misting their aquarium with non-chlorinated water. A hygrometer can be used to keep track of the relative humidity levels.

A highly recommended enclosure for your crabs is a terrarium with a removable glass lid. It is suggested to have a minimum of 20 liters of space for every two crabs in the terrarium.

To help manage the heat and water in the tank some like to use an under-tank heater. While this will allow for easier control of the tank’s parameters, it is important to make sure the tank doesn’t get too hot. To ensure the crabs do not get too hot some will place a 3-5cm liner between the tank and heater.

Creating the Landscape

When putting together your hermit crab home, sand is the best choice for the substrate. This is because hermit crabs need to have the ability to dig deep into the sand and be completely covered. When it comes to buying sand, you can purchase aquarium sand. It is suggested to rinse, dry, and then bake the sand at 300F so that the sand is sterilized. The great thing about sand is that when you clean your tank the sand can be washed and purified.

One great substrate choice is calcium-based sand. These are both inexpensive and come in a wide variety of colors to choose from.

Another good choice for the tank’s substrate is fiber bedding made for reptiles. This fiber is fine soil-like. Some people like to use crushed coral supplemented with sand. The substrates that are not recommended for use are wood shaving, gravel, sand made from calcium carbonate.

When you have decided on the substrate your crabs will need either between two to three inches or a depth three times higher than your largest crab, whichever is the greater volume. There has to be enough room for the hermit crabs to be able to burrow into during their molting phase so it’s not possible to have too much sand.

Besides the substrate, the crabs need a few more places to hide in the tank. You can purchase premade caves or create them using a mixture of rocks and driftwood.

Besides a place to hide in, crabs need objects to climb on and over. Choya or cholla wood is an ideal choice because of how easy it can be set up for climbing. However, you can place driftwood or coral in the tank and the crabs will happily climb over them as well. Experienced keepers say that it is important to frequently change the layout of your tank because of how smart crabs are and how much they enjoy exploring.

The tank needs to have at least four or five empty seashells per crab – yes, that’s a fair number of extra shells. As your crabby crustaceans grow they will need to have new and larger shells.

This tank needs to have two containers of water. One dish needs to be filled with clean dechlorinated water because chlorine is fatal for crabs to be around. Another dish needs to be filled with marine quality saltwater for the crab to soak in. The two containers of water need to have sides low enough that the crab can easily escape from. If your tank has crabs of varying sizes then it is important to place rocks of various sizes in the water dishes so that the smaller crabs do not drown and can escape from the dish.

The tank needs to have sufficient lighting for your crabs. A fluorescent LED bulb should provide enough light. The light needs to be on between 8-12 hours. It is important to not use high output UVB lights or it will harm the crabs. For the crabs to remain healthy they must have a regular night and day cycle with their tank lighting.

Best Plants: Plastic plants are a great choice.
Best Lighting:The best lighting for your tank is LED bulbs on a timer.
Best Decorations:Corals, driftwood, artificial caves.
Decorations to Avoid:Anything so tall the crab could use to escape.

Physiological Considerations for Hermit Crabs

Size: Golf ball size to tennis ball size
Lifespan: 10-15 years
Temperament: Semi-aggressive

Hermit crabs are known to be vulnerable while molting due to how soft their bodies are. Crabs must be isolated from their tank mates during this time. Crabs will normally molt twice a year. During this time the hermit crabs will shed their outer skin.

While moltinghermit crabs will consume a lot of water. This process will go on for several weeks, during which their skin will start to harden. It is important to not disturb your crabs during the molting process. Also, as disgusting as it sounds, don’t remove their old skin because it is normal for the crabs to eat it due to it being a source of calcium.

Once the crab has finished molting, they will move into a new shell so it is important to have several possible shells available for them to move into.

If hermit crabs get dropped on a hard surface, they can easily suffer injury or death.

It is important to never release hermit crabs into the wild. They most likely won’t survive and if they do, they can damage the local ecosystem.

Hermit crabs will keep themselves clean if they are provided with a source of clean freshwater and saltwater. Another way to help your hermit crab stay clean is to keep a sea sponge in their tank. The sea sponge will help to increase the humidity in the tank.

Society

Despite their names, hermit crabs are social creatures that need social interaction with other hermit crabs and prefer to live in large groups of their own kind. This social crab is known to travel in packs of upwards of a hundred other crabs as they search the beach looking for food and shells to move into.

One of the main reasons that hermit crabs travel in such large packs is because when there are more crabs there are more shells. Scientists have conducted experiments where laying down a single shell will cause a cascade of crabs to leave their shells. It starts with one crab leaving to put on the new shell and then soon all its neighbors start to switch around in order to find the perfect home to live in.

If this crab is left alone for too long it will become lonely, lethargic, and become sick more easily. However, the downside to housing multiple crabs in a single tank is that if there is not enough room the crabs may start fighting.

Besides breathing room, the other reason the crabs may fight is a lack of adequate food or water and not having enough shells to choose from. The fighting can be prevented by making sure you give an adequate amount of food and have several shells for your crabs to choose from.

Another way to help socialize your crab is to carefully remove it from its enclosure and play with it. As long as you are careful your crab will be safe and will not pinch you.

Gender, Breeding, and Reproductive Considerations

Breeding Hermit Crabs is a difficult task with only a few successful cases recorded. The best time to try is during January or February.

Part of having success in breeding hermit crabs is first to make sure that they have a proper environment. Start with a ten-gallon aquarium and make sure that it has a proper lid because hermit crabs are known for being avid climbers who take any chance to explore.

It is important to choose a quality heat lamp or heat rock that can keep the enclosure at 60F or above at all times.

You need to play at least one or two inches of sand into the container. It needs to be deep enough so that the crab will be able to burrow fully under the sand and be completely hidden from view.

Next, add branches and driftwood can be found in nature. You can also purchase premade logs and vines from a pet supply store and add those to your tank. The happier and more content your hermit crab is, the more likely they are to breed.

When their home is set up the next step is to determine the gender of your crabs. When they aren’t in their shells you examine them and the females have gonophores. The females also have larger pleopods on the left side of the crab’s abdomen.

You should add a saltwater tank with a pump that sprays water.

When the female’s eggs change color they can be dislodged from the shell and try to hatch them.

Nutritional Needs

The cornerstone of a healthy diet for Hermit crabs is a good pellet food supplemented with fruits and vegetables.  Hermit crabs eat slowly who only take small bites at a time and normally only at night.

If the crab is too small their claws may be unable to grab onto pellet food. If the crabs are having trouble eating solids you can feed them one teaspoon of powdered hermit crab food or simply crush their food pellets into a powder.

Hermit crabs are known to be omnivores so if you want to supplement your hermit crab’s diet with other food, there are a lot of choices. Dark leafy vegetables such as kale and broccoli are good choices. Other good choices are fruit like grapes, apples, and bananas. The important thing is to make sure whatever you choose is chopped up small enough and to place the food in their terrarium in the evening and remove any leftovers by the morning.

Besides fruits and vegetables, there are several other foods you can feed your crabs. Other foods include nuts, raisins, tree leaves and bark from deciduous trees, peanut butter, sushi-making quality seaweed, and no salt crackers. It is also possible to feed your crabs moderate amounts of cooked eggs, seafood, and meat. Another option is to feed your crabs freeze-dried shrimp and plankton as well as brine shrimp.

Because of hermit crabs being willing and able to eat such a wide variety there are no real exhaustive food lists. However, it is important to avoid feeding them any sort of highly acidic or citrus foods (such as tomatoes and oranges). It is also important to avoid starchy vegetables like potatoes and avoid iceberg lettuce because it has such little nutritional value. It is also best to avoid feeding your crabs any type of dairy product.

Despite not being able to feed Hermit Crab’s dairy products, they need a lot of calcium to ensure the health of their exoskeleton. There are a few things you can feed them to help provide sufficient amounts of calcium, such as cuttlebone, crushed oyster shells, coral sand, crushed eggshells, and calcium vitamin supplements.

It is important to make note that hermit crabs are incredibly sensitive to metal. This means that their water and food bowls need to be made of either ceramic or another nonporous, nonmetal material.

Your hermit crabs need to have access to clean, fresh water and marine-grade saltwater at all times. It is also important to add a water conditioner or a de-chlorinator to any tap water before serving it to your hermit crab.

Best Sustenance Food Type:Food pellets
Additional Food For Optimal Health:Calcium food supplements, various fruits, and vegetables.
Special Foods and Considerations for Best Color and Growth:Cuttlebone, crushed oyster shells, and eggshells can all be fed to help the exoskeleton grow strong.
When and How Often to Feed Fish Based on Life Cycle:Feed once at night and in the morning remove any leftovers.

Common Diseases and How to Avoid and Treat Them

The most common two health problems a pet hermit crab may encounter are stress and poisoning. If a crab has become stressed it slows down, becomes inactive, and possibly leaves its shell for an extended time without ever taking a new one. Hermit Crabs can be dressed by extreme hot or cold, loneliness, overcrowding, or bullying by another animal.

Poisoning happens when a hermit crab is misted with water that contains chemicals. A major symptom is if the crab drops its shell and will not take another crab.

If you notice any of these symptoms it is important to talk to a veterinarian:

  • The crab having excessive molting where it changes from shell to shell.
  • If your crab has a noticeable decreased appetite or activity.
  • The crab is staying outside of its shell and doesn’t look for another one.
  • When the crab loses either or both claws or limbs
  • A strong odor from inside the shell.
Best Antibiotics: Please consult your vet.
Treatments to Avoid: Please consult your vet.
Food Recommendations When Sick:A well-balanced diet.
Hospital Tank or Isolation Withing the Community Tank: Isolation tanks should be used and designed to mimic their primary habitat.

7 Facts About Hermit Crabs

  1. Hermit crabs are known to live up to 10 years.
  2. They can reach a length of six inches.
  3. They are land-dwelling creatures but need water and moisture.
  4. While Hermit crabs can be handled, they will pinch if they are frightened.
  5. As this crab grows up they will molt and change the shell they live in.
  6. When this crab molts it is important to offer then 3-5 different shells to choose from.
  7. Hermit crabs are social animals and need to be bought in either pairs or groups.

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