Hermit Crab Tank Size: General Tank Requirements to Take Note of!

A tank of at least 5 gallons in size is the minimum size required, and more significant is better. Ceramic or glass aquariums are the best options for hermit crabs, as they are durable and easy to clean. Some people keep their hermit crabs in 10-gallon tanks, but the minimum tank size for hermit crabs is 5 gallons.

The Population of Hermit Crabs in a Tank

10-Gallon Tank

There is no definite answer to this question as it depends on the size, number, and activity of your hermit crabs. A 10-gallon tank should be big enough for a few hermit crabs (up to four) to live comfortably. Ensure the water quality and temperature are perfect for them – they need a warm environment and clean water.

20-Gallon Tank

There is no definitive answer to this question as it depends on the hermit crabs’ size, diet, and tank conditions. However, a general rule of thumb would be to provide them with a source of food, freshwater, and enough space to move around. A 20-gallon tank is a minimum size for hermit crabs though they can live in larger tanks if provided with enough food and water.

5, 30, 40, 50, 79, 90-Gallon Tank

A hermit crab needs a minimum of a 5-gallon tank to start with. Once they are settled in, the tank size can be increased according to the available space. For example, a 30-gallon tank is ideal for 10-12 hermit crabs. A 40-gallon tank will hold 13 hermit crabs, and so on, up to a 50 or 79-gallon tank which can house 16-25 hermit crabs comfortably. 

Make sure the tank’s surface is covered in sand or gravel so the merits can climb and hide when they feel scared or threatened. Hermits need a limited amount of water (about one inch deep)and small pieces of food every day but should not be fed live insects as this can encourage them to build too many muroids (their shells).

Different Sizes of Hermit Crabs

Micro Hermit Crabs (Baby Hermit crabs)

Micro hermit crabs are a fascinating addition to any aquarium – they add a touch of the wild and look great on your tank’s décor. Here are four tips for keeping micro hermit crabs happy and healthy in your aquarium: 

  • A deep water depth is essential as they love to swim and hide away; make sure the tank you choose has at least that much space. 
  • Hermit crab needs lots of space to explore – a minimum tank size of 100 liters is recommended, although larger tanks work too. 
  • Ensure the enclosure isn’t too small, as this will lead to stressed-out hermits who may not survive long. 
  • If you have baby hermit crabs, provide them with some hiding place, so they don’t feel cramped in their enclosure (for example, create a rock formation or an overturned pot).

Small Hermit Crabs

Small hermit crabs are adorable creatures that make great pets. They require a minimum enclosure size of at least five gallons and need access to fresh water but don’t require any direct sunlight. Place the enclosure in a well-ventilated area away from other pets or children. Ensure the enclosure has a secure lid and plenty of hiding spots for your small hermit crab to explore!

Medium Hermit Crabs

Medium hermit crabs can be a lot of fun in your aquarium. They are easy to care for and come in various colors and patterns. Remember that the size of the tank you buy is based on how many hermit crabs you will be housing and their size. For example, a 10-gallon tank will house up to two medium-sized hermits, while a 20 or 30-gallon tank can accommodate up to six medium-sized hermits or one giant hermit crab. 

Large Hermit Crabs

Large hermit crab tanks are essential for a healthy and happy crab colony. They require plenty of space to roam, climb on, and hide from the other crabs in their tank. The tank size is up to you – as long as it can comfortably accommodate all your crabs! To ensure that your hermit crabs have everything they need, provide them with plenty of climbing surfaces and hiding spots.

Things to Consider When Choosing a Tank

Choose a Suitable Enclosure for Your Hermit Crabs

By following these tips, you’ll be able to choose the perfect size for your hermit crabs. First, ensure you never put live plants in the hermit crab tank, as this could kill them. Secondly, many types of enclosures are available, so choosing the right one for your hermit crabs is essential. The best type of enclosure is one with a lid so you can keep an eye on your crabs and ensure they’re safe. Finally, ensure the enclosure is large enough for your crabs and easy to clean. And lastly, make sure the enclosure is affordable and fits your lifestyle. 

Adding Substrate Into Hermit Crabitat

You don’t have to put substrate in the tank at all! Doing so can be harmful to your hermit crabs and coral reefs. Instead, add substrate to the crab tank when setting it up. Make sure to add enough for the crabs to dig down and bury their claws. Choose a substrate that is easy to clean – something like crushed coral or sandpaper would be ideal. Finally, ensure the substrate covers half of the bottom of the hermit crab tank – this will provide plenty of hiding places for your pets! 

Depth of Hermit Crabs’ Substrate

When raising small juvenile hermit crabs, the substrate can be at as shallow of a depth as 2 inches deeper than the size of your crab. For optimal conditions, more giant adult hermit crabs will need a substrate depth of at least 3 inches. The best substrate option is one that the hermit crabs can bury their claws in. Avoid using sand, gravel, or rocks as they create too much noise and disturbance – choose something like coconut coir instead. 

Substrate Consistency for Hermit Crabs

Hermit crabs need a fresh and consistent substrate to stay healthy and happy. A suitable substrate consistency is vital for the hermits as it provides them with a comfortable environment to live in. Avoid using too much sand or gravel, as this will clog up their digestive system and cause suffocation. Make sure the substrate is thick so they can bury their claws and legs inside it!

Heating and Lighting

Heating and lighting your tank is essential for their well-being, and a water change schedule is also necessary to keep them healthy and happy. Opt for a temperature range of 75°F to 85°F, and provide indirect light – direct sunlight can be too hot for them. Finally, add a hermit crab tank to your aquarium list today!

Under Tank Heaters

Before buying one, please select the correct size for your tank so that it will fit snugly. It would help if you also kept in mind the temperatures your hermit crab needs to thrive – their ideal range might not correspond exactly with what you set as their current environment. To ensure they are getting the optimal conditions, provide them with Lighting that mimics sunlight and humidity levels similar to those found outdoors.

Heat Lamps

Make sure to place the heat lamp near the tank’s water surface and ensure it’s not too high or low. Choose the correct type of heat lamp for your hermit crab tank – fluorescent or mercury vapor lamps are ideal options. A must-have item for any hermit crab tank is a good-quality heat lamp!

UVB Lighting

UVB lighting is essential for crabs to keep their shells clean and healthy. Heating and Lighting are among the most critical factors in a hermit crab tank, so get a light that emits a wavelength suitable for hermit crabs – around 290-320nm.


If the humidity level in the tank falls below the hermit crab’s preferred level, they may become stressed and sluggish. Make sure to place a humidifier in their tank if needed, and keep an eye on the humidity level, so you don’t over- or under-water! Also, ensure that their tank is clean and debris-free, giving them a healthy and happy environment.

Tip to Increase Humidity in Hermit Crabitat

Keeping humidity levels up in a hermit crab tank is essential for the well-being of your pets. Here are four tips to help you achieve the desired level: 

  • Check the humidity levels regularly and make necessary changes as needed. This can be done by taking readings with a hygrometer or monitoring software. 
  • Use an air purifier to create a clean environment for your hermit crabs, indirectly improving their humidity levels. 
  • Add a layer of moist sphagnum moss to the bottom of the tank for extra humidity; this will also add suppleness and stability to substrate surfaces, helping prevent excessive climbing behavior by your hermit claws.
  • Water dishes should always be filled with fresh water and changed daily – they must have access to moisture at all times.

Water and Food Bowls

Make sure the bowl size is appropriate for your crab – they need enough space but not too much so they can’t move around freely. Additionally, provide him with water and a food bowl to keep him hydrated and fed. You can add aquatic plants or shells to the tank to give him extra decorating options. Remember to turn off all lights in the room when you’re not home, so your crab doesn’t get used to bright light levels. 

Depth and Accessibility of the Bowls

One of the most critical factors you need to consider when choosing a bowl for your hermit crabs is accessibility. They should be able to quickly get water and food from the bowl no matter where they are situated in the house. Since hermit crabs love water and lots of it, be sure the bowls are deep enough so that they can swim around comfortably. Consider using a lid or cover if you want to keep predators and weather conditions at bay too!

Shells Shop for Hermit Crabs

Make sure to shop for shells that fit your hermit crab’s size and personality, and purchase them no smaller than 2 inches in size. If you can’t find shells that fit your needs, cannibalize small-sized ones to make them larger. Remember always to be safe when selecting shells for your hermit crabs – many are not safe for them!

Toys and Decorations

Toys and decorations also need to be as safe and sturdy as possible. Additionally, consider adding plants and rocks to give the tank a natural look. Compare tank sizes online or in-store to ensure you get the right size for your crabs. When it comes to toys and decorations, make sure they’re age-appropriate and compatible with each other.

Live Plants vs. Fake Plants

Fake plants are great for stimulating the senses but can be frustrating because of their chlorine scent. Live plants, on the other hand, provide hermit crabs with everything they need – a habitat and food. If you want to keep live plants in your home and don’t mind taking care of them (sterilizing their water before giving it to your crab), choose plants that don’t require watering or light, such as succulents or cacti.

Clean up Crew Isopods and Hermit Crabitat

Hermit crabs and isopods are the perfect tank mates for any aquarium. Not only do these small crustaceans help keep the tank clean, but they can also help feed your hermit crab. In addition, isopods can be used to feed your hermit crab as they eat any leftovers or debris that may accumulate in the tank. Ensure enough space for your hermit crab and its tank mates, as they’ll love you!