Species: Coenobita clypeatus (Purple Pincher / Caribbean Hermit Crab) | Difficulty: 2/5 — Easy | Hardiness: 3/5 — Moderate

Critter Cabana & Gresham Pet Supply — Keeping Your Pet Healthy & Thriving

At a Glance

Why We Love Them: Hermit Crabs are highly misunderstood. Far from the "throw-away" boardwalk pets they are often sold as, they are complex, fascinating, and incredibly long-lived social creatures when provided with a proper tropical setup.

The Humidity Warning (CRITICAL)

MODIFIED GILLS: Hermit Crabs do not have lungs. They breathe through modified gills. If the humidity in their tank drops below 70%, their gills dry out and they slowly suffocate to death. You must maintain a humidity of 75% to 85% at all times using a sealed lid (glass or plastic, not a screen).

The Social Rule

NEVER ALONE: Hermit Crabs are highly gregarious and live in massive colonies in the wild, often traveling in packs to find food and trade shells. You must keep at least two to three hermit crabs together. A solitary crab will become highly stressed and lethargic.

Housing & Enclosure

Tank Size & Environment

• Minimum Size: A 20-gallon "long" aquarium is the absolute minimum for a small group. They need significant floor space to molt and roam. (Do not use the tiny plastic "critter keepers" they are often sold in; these are death traps).
• Lid: A solid glass or plexiglass lid is required to trap humidity.
• Heat: Use a reptile heat mat (UTH). Place it on the BACK wall of the tank above the substrate line, NEVER on the bottom. (A bottom heater will cook a molting crab buried in the sand). Maintain air temperatures between 75-85°F.

Substrate (The Molting Requirement)

• Crabs must shed their exoskeleton to grow (molting). To do this safely, they bury themselves deep in the dirt for weeks or months.
• Substrate Depth: Must be a minimum of 6 inches deep (or 3x the height of your largest crab).
• The Mix: Mix 5 parts play sand to 1 part Eco-Earth (Coco Coir). Moisten it with dechlorinated water until it holds its shape like "sandcastle sand."
• NEVER DIG THEM UP: If a crab buries itself, it is molting. Digging it up will kill it.

Enrichment & Shells

• Provide climbing branches (cholla wood, cork bark).
• Shells: Always provide 3 to 5 extra, slightly larger shells per crab so they don't fight over them. Use natural shells with circular or D-shaped openings (Turbo shells are their favorite). Never buy painted shells, as the paint is toxic when they chip and eat it.

Diet & Water

Water (Two Pools Required)

Hermit crabs require access to two different water sources at all times:

1. Freshwater Pool: Treated with a tap-water conditioner (like Seachem Prime) to remove toxic chlorine.
2. Saltwater Pool: Mixed with marine-grade aquarium salt (like Instant Ocean). Never use table salt.

• Both pools must be deep enough for the crabs to fully submerge themselves, but include a ramp or plastic mesh so they can easily climb out and not drown.

The Diet

Commercial "Hermit Crab Pellets" are often full of toxic preservatives and lack nutrition.

• Staple Diet: They are scavengers. Feed them a varied diet of raw shrimp, dried insects (bloodworms, mealworms), unseasoned scrambled egg, fresh fruits (mango, coconut), and dark leafy greens.
• Calcium: Always provide a piece of cuttlebone or crushed oyster shell for exoskeleton health.
• Leaf Litter: Dried oak or Indian almond leaves should be scattered on the floor for them to munch on.

What We Stock & Use in Our Stores

Care sheet compiled by Critter Cabana & Gresham Pet Supply.

Last updated: 2026-08-04

How We Keep Them at Critter Cabana & Gresham Pet Supply

• Oregon Winter Furnace Air vs. Molting Humidity: When Pacific Northwest furnaces kick on from October through April, indoor room humidity drops fast and dries out small enclosures from the top down. Rather than misting the spider or invert directly (which stresses terrestrial species and invites stagnant mold), we keep Hermit Crab at 75-85% (CRITICAL) by using a deep moisture-retaining substrate bed (ReptiSoil + Coco Fiber + Sphagnum Moss), overflowing the water dish slightly into one corner, and maintaining cross-ventilation.
• Safe Room Heating in the Willamette Valley: If your house drops below 65°F on winter nights, never stick a heat pad on the bottom of a burrowing invertebrate tank—they dig down to escape heat and will cook themselves. Use a low-wattage side-mounted heat mat on a digital thermostat or warm the room ambiently to 75-85°F.
• Stocked at Newberg & Gresham: At Critter Cabana (Newberg) and Gresham Pet Supply, we stock acrylic and glass invertebrate enclosures, cork bark flats and tubes, bioactive substrates, flightless fruit flies (D. melanogaster and D. hydei), pinhead to adult crickets, dubia roaches, and live Temperate White Springtail and Isopod cultures.

Common Questions (FAQ)

How do I keep my Hermit Crab warm and humid enough during an Oregon winter?

Target 75-85°F and 75-85% (CRITICAL). When Oregon winter furnaces dry out the air, use a deep 3–5 inch substrate mix of Zoo Med ReptiSoil and coco fiber, keep a shallow water dish filled, and dampen one corner of the substrate rather than misting the animal directly. Never put a heat mat underneath a burrowing invertebrate enclosure.

What size enclosure does a Hermit Crab need?

An adult Hermit Crab thrives in 20 Gallon (Minimum for a pair) with secure ventilation. For terrestrial tarantulas and scorpions, floor space and deep substrate matter most (keep open fall height low so heavy-bodied species cannot rupture their abdomen); for arboreal species, prioritize vertical cork bark tubes and cross-ventilation.

Can I put isopods in a Hermit Crab bioactive enclosure?

Around molting tarantulas and scorpions, skip protein-hungry large isopods and stick to Temperate White Springtails (or gentle Dwarf White isopods in humid detritivore setups) so a soft, newly molted animal is never nibbled.

Where can I find Hermit Crab, cork bark, and feeder insects in Oregon?

We stock live invertebrates, tarantulas, jumping spiders, cork bark flats and tubes, bioactive substrates, and gut-loaded feeder insects at our two exotic animal stores: Critter Cabana in Newberg (514 E First St, 503-537-2887) and Gresham Pet Supply (2185 NW Burnside Rd, 503-665-7606).