TERRARIUMS & SUBSTRATE
Surf through the topics below to understand everything you need to get started caring for your pet hermit crabs.
The general rule is 5 gallons of terrarium volume per one hermit crab, with up to 10 gallons per larger hermit crab. Land hermit crabs are very social so you should own a minimum of 2 pet hermit crabs, but preferably 3 or more. This means you’ll need a minimum tank size of 10 gallons. Land hermit crabs are native to warm, humid climates so you will need an aquarium/fish tank with a glass bi-fold lid to keep the humidity and temperature stable. Reptile tanks are more expensive and have screen lids, so skip these.
The best priced new tanks can be found at Petco and Petsmart, but don’t forget to check on Craigslist, Facebook Market, yard sales, etc. for good deals. Some local pet/fish stores also have reasonable pricing, especially for custom tanks if you have a specific space you are trying to fill.
The minimum depth for the substrate is 4-6 inches regardless of tank size. Keep this in mind while choosing a terrarium. Not only do land hermit crabs like digging, but they require the ability to become completely submerged during molting.
The best substrates are mixtures of sand and coconut fiber with a ratio of 1 part coconut fiber to 4-5 parts clean play sand (for sandboxes). This sand mimics their natural coastal habitats, while the coconut fiber helps to maintain moisture/humidity in the crabitat. Replace the substrate every 4-6 months assuming you are diligent about cleaning out their food messes a regular basis.
Most sand sold in pet stores is expensive but perfectly fine. Be sure to avoid calcium sand. You can purchase a 50 lb bag of play sand at your local hardware store for around $6. Zoo Med's Eco Earth coconut fiber substrate sold in the brick form is the most cost-efficient option, just be sure to let it partially dry out before mixing.
3. TEMPERATURE AND HUMIDITY
The temperature required for your terrarium is between 70-80 degrees. The humidity requirement is between 75%-85%. To ensure these levels are stable you will want to have a gauge in the terrarium, placed near the middle to provide the most accurate reading.
REPTI ZOO's terrarium thermometer and hydrometer is a very accurate and compact device with a digital display. Also, this meter attaches to the glass of your terrarium with a suction cup so it can be relocated as you redesign your habitat.
There are multiple ways to achieve the proper temperature in the terrarium, however a heat lamp is not one of them. Plan on getting an overhead light for two reasons: 1) crabs need a day/night cycle just like in the wild; 2) it adds warmth to the terrarium without creating a "hot spot" that can ultimately cook your new pet hermit crabs.
If you live in a warm region: You should be able to get away with just using an overhead UVB light. Keep an eye on your temperature gauge to determine if you need something more.
If you live in a cold region: You will likely need a heating pad. It should be placed on the back of the tank along the upper portion of the glass which is not filled with the substrate, rather than under the tank. iPower Reptile Heat Pad Under Tank Terrarium Heater Heat Mat for Small Animals is well regarded as one of the best heating pads on the market. It comes in multiple sizes and is UL listed which is important for heating elements. The BN-LINK Digital Heat Mat Thermostat Controller is a great addition to the heat mat because it allows you to control the exact temperature you want the crabitat to maintain, and helps prevent your pet hermit crabs from over-heating.
If you live in the United States, you likely do not live in conditions that will meet a land hermit crab's humidity requirement year-round. To achieve this you have multiple options that can be used individually or simultaneously depending on what readings you have on your humidity gauge. Keep in mind you should already have a rather airtight lid to maintain and stabilize your humidity as discussed above.
a.) Start with a spray bottle. Mist the substrate and moss (see below) every couple days to keep things moist (i.e., sand castle building consistency). We recommend using salt water for this, so plan to have a dedicated spray bottle for this purpose.
b.) Sphagnum moss is a must. Not only will your pet hermit crabs snack on it, but it retains moisture that will slowly be released. Use loose moss in a hide-away hut and/or purchase a feature such as a moss bridge. Setting up high humidity zones with masses of moist moss not only increases the humidity in the habitat, but provides a space the hermit crabs can visit if they are craving a little more humidity.
c.) As a last resort, you may need to facilitate evaporation from your water source. To do so, the Tetra Whisper Easy to Use Air Pump is designed for small aquariums so it is perfect for your water bowl. This device is very well reviewed, quite affordable, and has a significant effect on humidity levels. It is unlikely you will need this if you have incorporated the methods listed above.
Again, you have a few options so see what methods work best for your crabitat and location.