Hermit Crab Heat and Humidity: What You Need to Know
Hermit crabs need a warm, humid crabitat.
They breathe through modified gills, which need moisture in the air to function properly. They also need warmth to stay active and maintain normal behaviors like eating, digging, and molting.
The goal is simple: keep the temperature and humidity within the right ranges.
- The right temperature and humidity ranges
- How to measure them accurately
- The safest way to heat a crabitat
- How to maintain humidity without misting
- The most common heat and humidity mistakes
What Temperature Do Hermit Crabs Need?
Aim for 75–85°F.
Small changes throughout the day are normal. If the temperature regularly falls outside that range, adjust your heating setup.
What Humidity Do Hermit Crabs Need?
Aim for 70–85% humidity.
Small changes throughout the day are normal here too. Humidity may drop temporarily when you open the crabitat for feeding or maintenance.
How Do You Measure Heat and Humidity?
Use a digital thermometer and hygrometer placed just above the substrate near the center of the crabitat.
Keep the gauges away from the heat mat so you’re measuring the crabitat, not the heat source.
Check your gauges regularly. You’re looking for the right range, not one perfect number.
What’s the Best Way to Heat a Crabitat?
Use a heat mat on the outside back or side of the tank, above the substrate line. Never underneath the tank.
The goal is to warm the air inside the crabitat, not the substrate. Hermit crabs burrow to molt and may dig all the way to the bottom.
Putting a heat mat underneath the tank. Always mount it on the back or side, above the substrate line.
How Do You Maintain Humidity?
Start with the lid. A secure glass lid helps keep warm, humid air inside the crabitat.
Properly prepared substrate also helps hold moisture. Use a 5:1 mix of play sand and coco fiber. Damp moss can provide another source of moisture.
If humidity is too low, check the lid and substrate first. Misting may raise the number temporarily, but it doesn’t fix the reason humidity is escaping.
Misting the crabitat to raise humidity. Focus on maintaining stable humidity with a secure lid and properly prepared substrate instead.
75–85°F. 70–85% humidity.
Use digital gauges to monitor both, heat from the back or side, and use a secure glass lid to help hold humidity in.