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FISH / new pets

A Set-up Guide for Your New Pet Hermit Crab

Tips for home, health and fun


Six things to know about your hermit crab

  • Hermit crabs can live up to 10 years
  • They can grow up to 6 inches long
  • They are land dwellers
  • They are omnivorous
  • They can be handled, but will pinch if threatened or scared
  • They molt (shed their skin) and change shells as they get bigger

Your hermit crab’s home

Despite their name, hermit crabs are social, so you can keep a few of them together. Choose a terrarium with at least 5 gallons of space for every two crabs. Keep the terrarium in a low-traffic area, away from direct sunlight and drafts. The terrarium should have a hood to keep in the humidity — and your pets.

What to put in the (hermit) crab shack

Line the bottom of the terrarium with 2 to 3 inches of washed aquarium gravel or fine reptile bark bedding; they’ll burrow into it when they’re molting.

Add a shallow water dish — not too deep — for your crabs to soak themselves. If some crabs are smaller than others, put a sea sponge in the bowl so the smaller guys can climb out.

Stock the habitat with hiding places and at least two larger empty shells per crab — they can scope these out for housing as they grow.

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Heat & lights

  • Put a fluorescent bulb under the terrarium hood to light the habitat for eight to 12 hours a day. Turn it on when you feed the crabs their breakfast and off when you feed them dinner.
  • The terrarium temperature should be between 75 and 80 degrees Fahrenheit during the day. Use a thermometer to monitor the temperature.
  • If you use an under-tank heater, cover it with at least an inch of bedding, so your crabs don’t get uncomfortably hot.
  • Hermit crabs thrive at humidity levels between 50% and 80%. Mist their terrarium with non-chlorinated water as necessary and use a hygrometer — a device that measures humidity — to keep track.
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Help keep your hermit crab healthy

Hermit crabs can be vulnerable while molting, because their bodies are soft. Isolate them from their roommates during this time.

Don’t drop hermit crabs onto a hard surface; doing so can injure or kill them.

Never release hermit crabs into the wild. They aren’t likely to survive and if they do, they can harm the local ecosystem.

If you notice any of these symptoms of illness or distress, talk to a PetSmart store associate or a veterinarian:

  • Decreased appetite or activity
  • Staying outside of the shell
  • Excessive molting
  • Lost claws or limbs
  • Strong odor from inside the shell


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The PetSmart Promise: If your pet becomes ill during the initial 14-day period, or if you’re not satisfied for any reason, PetSmart will gladly replace the pet or refund the purchase price.