top of page

Setting Up A Successful Hermit Crab Tank

Updated: Apr 22

The secret to keeping Hermit Crabs happy and healthy, is all based on the way you set up and keep your tank. It is crucial to set up your tank correctly from the very beginning to give your crabs the best chance at having a good life in captivity.

But what if you have already invested in those expensive Krabooz items or that tiny 20L fish tank? Don't worry, you can still fix it and get your crabbies life back on track and thriving in no time! The cheapest way to set up your tank, is by doing it correctly from the start. This will prevent you having to fork out more money to set up all over again.

Let's talk essentials! The key elements that your Hermit Crab will need in order to survive and thrive.

Essentials -

  • Glass Fish Tank - That is all you need when it comes to finding a home to house your crabs. Just a plain old glass fish tank/aquarium with a glass lid. You don't need anything fancy, and you can often find cheap fish tanks on Gumtree or Facebook Marketplace. Secondhand fish tanks with no cracks are the perfect home! Each Hermit Crab you own will need a minimum of 38L each, this means you must have a tank that is a minimum of 75L in order to house 2 crabs. If you can afford to go bigger, it is highly recommended.

  • Substrate - The stuff that goes in the bottom of the tank! All you need is regular washed play sand and Coir Peat. Play sand can be found at Bunnings, or most hardware's and Coir Peat is available at Bunnings and most gardening stores. You need 8 parts of play sand to 1 part of Coir Peat.

  • Pools - Your tank will require 1 salt pool and 1 freshwater pool. This is crucial for Hermit Crabs to drink, bathe, and fill their shells with water. This also aids in humidity within the tank.

  • Heat Source - Heat is crucial in a Hermit Crab tank and can be the most common factor for a Hermit Crabs death. You will need either a reptile heat mat or a reptile heat cord. These MUST be placed on the BACK of the tank, NEVER on the bottom of the tank.

  • Insulation Mats - Insulation is so important in keeping the heat reflecting back into your tank, instead of away from it. Insulation can save up to 20% of your heat! These should be placed on the back or sides of the tank, sitting over the heat source. These are heat proof and are not a fire hazard.

  • Water Conditioner - Seachem Prime is the best possible product you can use in the water that goes into your pools. Regular tap water is filled with all sorts of nasties that are unsafe to our crabs. Using Seachem Prime in your water pools will remove Ammonia, Nitrites, Nitrates, Chlorine and Chloramine, all which are toxic to Hermit Crabs. This should be used in both the saltwater pool and freshwater pool.

  • Thermometer & Hygrometer - You will need to place a thermometer and hygrometer within the tank to keep track of the heat and humidity levels. This is vitally important; temperatures and humidity must be kept at steady levels constantly.

  • Marine Grade Salt - The only salt that should ever be used in your pools is high quality marine salt. No table salt, cooking salt, salt flakes, Celtic salt, Himalayan salt, or Krabooz salt crystals. Simple fish marine salt is all you need. This is filled with the correct vitamins and minerals that aid in your Hermit Crabs health.

  • Food Bowls - Supplying somewhere for your Hermit Crabs to get their dinner is important. A small food bowl is all you need to feed your crabs their daily meals.

  • High Quality Foods - A high quality and varied diet is extremely important in aiding your Hermit Crabs health. Stay away from pet store marketed crab foods such as Krabooz, crab pellets, crab powders etc. These are filled with preservatives and lack the required dietary needs that Hermit Crabs need to survive.

  • Natural Shells - Natural shells are the best thing you can offer your crab as a home. Stay away from painted shells, these are covered in toxic paints and when consumed, can ultimately result in illness or death. The toxins do absorb into the shell, so please do not think you can remove the paint and scrub them clean. Simply place the painted shells into the bin. Offer 6 spare shells per crab, in similar sizes and various styles.

  • Light Source - Adding a light to your tank (aquarium light) helps to regulate your crabs' days. Giving them 12 hours of daylight and 12 hours of dark. This should be placed above the tank.

  • Supplements - Offering supplements to your crab is a must, these aid in those essentials that they need in their diet that they may not find in other foods. Supplements that should always be on offer in your tank are Greensand, Worm Castings, Insect Frass, Leaf Litter and Calcium.

  • Friends - Hermit Crabs naturally live in large colonies in the wild and despite their name, they can and do get awfully lonely. It is highly recommended to house them with other Hermit Crabs.

Below we will talk about extras and enrichment products. These are not the absolute necessity in order for them to survive, however they do aid in the enrichment and overall happiness of your crab.

Enrichment -

  • Plants - Whether you use fake plants or real plants, this is a great way to add a natural environment to your tank and give your crabs something to climb or hide in.

  • Moss Pit - Adding dampened Sphagnum Moss to your tank will not only aid in humidity, but it will also give your crabs a nice hangout spot. Most captive Hermit Crabs love sitting or sleeping in their damp moss pits, as well as munching on the moss too.

  • Pool Bubblers or Filters - Adding bubblers or filters to your pools will not only aid in humidity, but it also means less work for you! By aerating the water, you can change the water out less often.

  • Natural Wood - Using Hermit Crab safe woods is a great way to add in that natural feel to their enclosure, they will also thoroughly enjoy climbing it.

  • Hideouts - Hermit Crabs can feel quite vulnerable when constantly out in the open, giving your crabs a place to hide is a great way to give them a chance for a time out if they are feeling afraid and unsafe.

  • Crab Wheel - Hermit Crabs will naturally walk hundreds of kilometers a day in the wild, by providing them a wheel, this will mimic their natural need to walk long distances. Owners often find their crabs take a liking to their wheels and will often spend hours a day just going around and around. This is also a fantastic source of exercise.

  • Hammocks, Vines & Second Levels - Being naturally excellent climbers, Hermit Crabs love spending their time climbing and being up high. By adding in climbing vines and hammocks, you offer those activities to keep your crabs entertained.

Below we will delve deeper into how exactly we need to set up a successful tank.


Australian Hermit Crabs need a minimum of 15cm of sub (6”) This helps even the largest Crab to safely moult beneath the sand. Sub should be made up of play sand and coir peat and mixed as 8 parts play sand to 1 part of coir peat.

Coir peat blocks should be soaked in Primed Water, wringed out, but still damp and mixed with the sand inside the tank until completely combined.

- How to Measure 8:1 ratio –

You can use any container/bucket size for your measurements. For this example, we will use a 5L ice cream tub. Scoop 8 ice cream tubs of sand into your tank, then scoop 1 ice cream tub of coir peat and mix inside the tank. Repeat this, adding 1 tub of coir peat after every 8th tub of sand until your sub is at the minimum level of 15cm.

Substrate should be sandcastle consistency, if you poke your finger in, it should stay shape. Substrate should not be soaking wet or too dry. After time, the top surface of the sub will eventually dry out due to the heat, this is completely normal. As long as the sub underneath is still sandcastle consistency. You can test this by poking your finger in the sub or pushing a straw into the sub up against the glass, the straw tunnel should stay together.


Hermit Crabs require both fresh and saltwater pools to drink, bathe, spawn zoea and fill shell water. Pools must be deep enough for your largest Crab to fully submerge its entire shell. This ensures that your crabs can successfully fill their shells with the water that they need.

Pools can be made from anything from take away containers, plastic Tupperware or small glass Aquariums and bowls. Both Pools need an easy way in and out, this prevents drowning. Possible access points include fish egg crate, wood, plants, stones etc. Both Pools should be treated using Seachem Prime water conditioner. The salt pool should also contain a high-quality marine salt.

- How often to change your water –

No Bubblers/Oxygenation – Every 48 hours

Bubblers – Once a week

Filters – Every few months

Adding bubblers/filters to your Pools keeps your water fresher for longer and aids in humidity. Bubbler equipment can be found at most pet stores/aquariums.

- Equipment Required for Bubblers –

Air Stones

Aquarium Tubing

Aquarium Air Pump

Line Splitter (only needed if a single tube pump)


Heat Mats or Heat Cords are the only heat sources that should be used in a Hermit Crab Tank. Heat lamps are not a safe or appropriate source of heat and should not be used. When adding your heat mat or cord, it should be placed on the outside of the tank, sitting above the substrate level. You only want to heat the air, not the sand. Never place your heat source under the tank, this will burn any moulting crabs. Heat sources should be added to the back/sides of the tank only.

Australian Hermit Crabs require heat between 27-32.c degrees. With the optimum temperate being 28. Adding insulation to your tank will help keep the heat at an optimum level and reduce heat loss. Insulate over the top of the heat mats/cords using insulation mats.


Adding a Thermometer/Hygrometer to your tank will help ensure that your temperature and humidity are at the correct levels. The probe or gauge should sit 2-3cm above the substrate level, in the middle of the tank. This will give the most accurate reading. Humidity should sit between 70-85%.


Offering a fully balanced and varied diet will ensure that your Hermit Crabs are staying healthy. This can be offered using fresh and dried foods. Hermit Crab products such as Krabooz, Pellets, Treats or Flakes found in pet stores should be avoided. These do not offer a balanced diet, catering for all of the nutrients that your Hermit Crabs need to survive and thrive. Offer fresh and dried foods from the safe food list and only purchase high quality handmade foods from the approved Australian Sellers.


Hermit Crabs should only be offered Natural Shells, free of paint or other polishes. Painted shells are dangerous as the paint can peel off and be consumed by the Crab.

If your Crab changes into a natural shell, remove the painted shell and bin it. Do not pick/wash the paint off as the chemicals have already absorbed into the shell. If you purchase/adopt a Hermit Crab that is in a painted shell, do not try to remove the Crab from its shell. Simply offer natural shells in various sizes/styles and your Crab will change when it is ready to do so.

There should be at least 6 spare shells per Crab available in the tank, suited to their size. Offer shells that are slightly larger than what your Crab is currently wearing. For more accuracy, you can measure the opening of your crabs' shells and order shells that are slightly bigger.


  • Krabooz Products (these are not appropriate for proper Hermit Crab Care and are simply a marketing ploy to sell Crabs as easy children’s pets) These include, Foods, Treats, Heat Mat, Tank, Water Conditioner, Salts etc. Usually sold to encourage the death of your crab, forcing you to return to the store and spend money purchasing more crabs. And that is the vicious pet store cycle.

  • Pellet Foods, these do not offer a balanced or sufficient diet to support your crabs' nutritional needs.

  • Table Salt, Rock Salt, Himalayan Salt, Cooking Salt, Celtic Salt etc. Only use High Quality Marine Salt. This offers the nutrients that your crabs need.

  • Plastic Tanks, Mesh Wire Tanks, Krabooz Tanks, Reptile Tanks that are not enclosed fully.

  • Hermit Crab Labelled Sand, Colored Sand, Gravel, Colored Gravel, Red Sand, Calcium Sand, Tanbark, Reptile Bedding. You only need simple play sand and coir peat.

  • Colored Shells, Painted Shells, Lacquered Shells, Shells with holes. The chemicals in the paint are dangerous if consumed. Shells with holes will not let your crab safely hold its shell water and will leak.

  • Pool Sponges. These only harbour bacteria and offer no beneficial purpose within your tank. They are definitely not needed and will only dirty your water quicker.

*Tanks pictured belong to the owner of The Happy Hermie.

Recent Posts

See All


bottom of page