A good crabitat gives hermit crabs the conditions they need to dig, molt, climb, eat, and explore.

This guide covers the essentials and how to put them together.

Start With the Right Tank

A glass tank helps hold the heat and humidity hermit crabs need.

Many hermit crabs are sold in small plastic mesh carriers that are not suitable crabitats. They don’t hold the warm, humid conditions hermit crabs need to breathe properly, and they don’t provide enough space or substrate for digging and molting. They’re meant for transport, not long-term care.

Plan for at least 10 gallons of tank space per hermit crab. Two crabs need at least 20 gallons. Five crabs need at least 50. If you can go bigger, go bigger.

Use a secure glass lid rather than a screen lid. A glass lid helps hold heat and humidity inside.

Build the Right Foundation

Hermit crabs burrow to rest and molt, so they need substrate deep enough to dig and stable enough to hold their tunnels.

Use a mix of five parts play sand to one part coco fiber. Sand provides structure. Coco fiber helps retain moisture.

Aim for at least 6 inches of substrate, or three times the height of your largest crab, whichever is deeper. Squeeze a handful. It should hold its shape like sandcastle sand.

Keep It Warm and Humid

Hermit crabs breathe through modified gills, which need humid air to function properly.

Aim for 75–85°F and 70–85% humidity.

Mount the heat mat on the back of the tank above the substrate line, never underneath the tank.

Fresh Water and Salt Water

Provide two pools at all times: fresh water and marine salt water.

Both should be deep enough for your largest crab to fully submerge, shell and all, with a safe way in and out for crabs of every size.

Treat tap water with Prime Water Conditioner before use. For salt water, use a marine salt mix like Instant Ocean. Table salt and freshwater aquarium salt are not substitutes.

Feed a Variety

Build a fresh buffet each day with Complete Meals and Single Ingredients. Keep The Core — Green Sand, Worm Castings, and a calcium source — available at all times.

Complete Meals and Single Ingredients rotate. The Core stays available.

Learn the Buffet Method →

Always Have a Shell Shop

Offer three to five appropriate, natural, unpainted shells per crab in a range of sizes. As your crabs grow and change shells, adjust the shell shop to match their needs.

A well-stocked shell shop gives your crabs choices and helps reduce competition over shells.

Add Places to Climb and Explore

Cork bark, cholla wood, moss, leaf litter, branches, and other climbing and foraging materials add usable space and enrichment to the crabitat.

Rearrange some of these items occasionally to give your crabs something new to investigate.

Don’t Forget a Day and Night Cycle

Hermit crabs are most active at night, but they still need a regular day and night cycle. Aim for about 12 hours of light and 12 hours of darkness.

A simple LED on a timer works well. Keep the crabitat out of direct sunlight, which can quickly overheat the tank.

Keep the Air Clean

Keep candles, air fresheners, essential oils, bug sprays, smoke, and harsh cleaning products away from the crabitat.

Avoid spraying or using scented products near the tank, especially when the lid is open for feeding or maintenance.

Build the Crabitat First

Get the essentials right before worrying about décor. Once the crabitat is stable, add climbing, hiding, and foraging areas that give your crabs more to do.

Quick Crabitat Checklist

• Glass aquarium with at least 10 gallons of space per crab
• Secure glass lid, not a screen lid
• Deep 5:1 substrate of play sand and coco fiber
• Heat mat mounted on the back of the tank
• Temperature between 75–85°F
• Humidity between 70–85%
• About 12 hours of light and 12 hours of darkness
• Fresh water and marine salt water
• A shell shop with 3–5 appropriate, natural shells per crab
• Places to climb, hide, and forage
• A varied diet using the Buffet Method