New Land Hermit Crab Owner FAQ

Q1. What size tank do I need?

Plan for at least 10 gallons per small-to-medium crab, with substantially more room as crabs grow — this is the Land Hermit Crab Owners Society’s minimum, and it works as a practical planning figure for a beginner buying a tank. What matters is usable space, not just volume: enough floor area and substrate depth for crabs to molt away from each other, plus room for pools, shells, hides, and climbing. Small plastic carriers and wire cages are not acceptable homes.

Source note: the three references frame it differently — HCA’s care sheet gives a 10-gallon floor for small crabs and roughly 5 gallons per crab for long-term housing of small crabs (with 75+ gallons for a fully grown one); CSJ calls a 10-gallon tank suitable only for two very small crabs and suggests 29 gallons as a more practical starting point. Sources differ; no single number is asserted as universal, and the FAQ leads with LHCOS’s explicit per-crab minimum.

Sources: LHCOS Habitat Standards (https://lhcos.org/hermit-crab-care-education-standards/habitat-standards-for-ethical-hermit-crab-care/); HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); CSJ new-owner checklist (https://crabstreetjournal.org/blog/the-newbies-guide-to-hermit-crabs/)

Q2. What goes on the bottom of the tank?

A mix of children’s play sand and coconut fiber (sold as Eco Earth or coco fiber), roughly five parts sand to one part fiber. Dampen the mix until a squeezed handful holds its shape like a sandcastle — firm enough to tunnel in without collapsing, not dripping wet. Make it at least 6 inches deep, or about three times the height of your largest crab, whichever is deeper.

Shallow substrate is inadequate and must be corrected. Note, though, that a surface molt by itself does not prove the setup is bad — current CSJ guidance says surface molts can occur in otherwise stable, suitable habitats. The real hazard is that a soft crab is vulnerable to interference and injury from tankmates, so protect it (see Q11).

Sources: HCA substrate guide (https://hermitcrabassociation.com/phpBB/viewtopic.php?p=852645); CSJ surface-molt guide (https://crabstreetjournal.org/blog/surface-molts/) — accessed 2026-10-04

Q3. How do I measure the 5-to-1 sand-to-fiber ratio?

The 5:1 figure is approximate, not a precise formula — close counts. What matters is the result: substrate that holds a tunnel without collapsing. Measure by volume, using dry ingredients — for example, 5 cups of dry sand to 1 cup of dry loose coconut fiber, mixed well in a tub before it goes into the tank, then repeat. Don’t dump dry ingredients straight into the tank; they won’t mix evenly once inside.

Note: a compressed brick is not the same thing as a gallon of loose fiber — measure the fiber after it is expanded and fluffed. Skip bag-and-brick shortcuts: a “half brick per 50-pound bag of sand” tip circulates in groups, but it was not found in the sources reviewed. Skip the pounds-to-gallons conversion entirely; product yields and bulk densities vary by brand, so volume is the only dependable measure.

Sources: HCA substrate guide (https://hermitcrabassociation.com/phpBB/viewtopic.php?p=852645) — accessed 2026-10-03; CSJ new-owner checklist (https://crabstreetjournal.org/blog/the-newbies-guide-to-hermit-crabs/) — accessed 2026-10-03

Q4. What temperature and humidity do they need?

For Purple Pinchers: 75–85 °F, with about 80 °F as the sweet spot. Below roughly 70 °F for extended periods, crabs go dormant and can die. Humidity: 70–85% is the commonly cited band; note that HCA’s Purple Pincher sheet caps its recommendation at 80% because higher humidity encourages mold (it also says higher is safe for the crabs). Hermit crabs breathe through modified gills, so humid air matters as much as warmth.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); HCA Purple Pincher species sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?t=92452); LHCOS Habitat Standards (https://lhcos.org/hermit-crab-care-education-standards/habitat-standards-for-ethical-hermit-crab-care/)

Q5. My humidity is high but my temperature is low. What do I do?

Two different problems, two different responses — don’t mix them up.

Cold tank (temperature too low): fix the temperature first. Warming the air doesn’t magically raise relative humidity — at the same moisture level, warmer air actually reads lower on the humidity gauge. What heat does is drive more evaporation from the pools and damp substrate, putting more moisture into the air. Mount the heat mat on the back or side wall, never underneath — buried crabs can be cooked. Check your mat maker’s instructions for how high the mat should sit relative to the substrate line (Ultratherm pad guidance from The Bean Farm — a seller’s product page, model-specific seller guidance, not a universal manufacturer manual — advises keeping the pad mostly above the substrate line). Control the heat with a thermostat — a dimmer only reduces power and doesn’t respond to temperature, so it is not equivalent to thermostat control; place the probe per the controller’s instructions and confirm it is compatible with your mat. On insulation: actual mat and controller manuals govern compatibility, mounting, probe placement, and insulation — some manufacturers prohibit covering their pads, while others allow insulating around certain models; follow your own product’s instructions, and never insulate in any way the manufacturer prohibits.

Too much moisture (constant saturation, heavy condensation, flooding): this is not a “raise the humidity” situation — adding moisture makes it worse. Cut back on misting, make sure the lid seals properly with small vents for airflow (not airtight), and slightly increase ventilation. Do not add large water bowls or damp moss to fix excess moisture; those are humidity-raising measures for the opposite problem.

Sources: CSJ new-owner checklist (https://crabstreetjournal.org/blog/the-newbies-guide-to-hermit-crabs/) — accessed 2026-10-03; HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457) — accessed 2026-10-03; Ultratherm pad guidance (https://beanfarm.com/products/ultratherm-heat-pads-6-x-17-in) — accessed 2026-10-04; HCA forum admin threads on insulation — accessed 2026-10-03

Q6. What kind of shells do they need?

Natural, unpainted turbo-style shells. Keep at least 3 to 5 spare shells per crab — include shells in the crab’s current size as well as modestly larger options, and let the crabs choose. A commonly used fit reference is a shell opening roughly the size of the crab’s large pincer, but that rule isn’t universal — crabs regularly pick shells that look too big or too small to you, so verify opening measurements, shape, weight, and your species’ preferences when buying (Etsy-style sellers that list exact opening measurements help). For Purple Pinchers, tapestry turbos and striped/Mexican/grey turbos are preferred types. Keep painted, glazed, dyed, or coated shells out of the tank — keepers avoid them because of toxic-paint concerns, though that avoidance advice is keeper caution, not a demonstrated chemical analysis. Shell shortage is serious: a crab short on options may force a tankmate out of its shell and steal it.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); HCA Purple Pincher species sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?t=92452)

Q7. Where can I buy good shells, and how do I prepare them?

Natural shells are sold online and in craft stores; several keepers buy from Etsy sellers that list exact opening measurements. Choose by species suitability and measured opening size rather than a marketplace name alone. Before offering new shells, clean and prepare them using a verified method: boiling heat-safe empty shells in dechlorinated water for about five minutes is one such method — boiling is preparation, not proof of complete sterilization. Soak and carefully check each shell first to make sure no crab is hiding inside, and never boil an occupied shell; soaking alone doesn’t prove a shell is empty, so inspect it. Emergency rinsing (a quick rinse with conditioned freshwater when you need shells immediately) is separate from routine preparation.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); CSJ tank-cleaning guide (https://crabstreetjournal.org/blog/how-do-i-clean-my-hermit-crab-tank-crabitat/) — accessed 2026-10-04

Q8. What do I feed them?

Think varied scavenger diet: fruit and protein (meat, insects, seafood) daily, plus vegetables and plant matter, with calcium (cuttlebone, crushed coral, eggshell) available at all times. Swap out fresh food every day so it doesn’t mold in the warm, humid tank.

On commercial hermit crab foods: both major references lean against making pellets the foundation of the diet. HCA and CSJ note that ethoxyquin and copper sulfate appear on many pellet ingredient lists and advise against pellet-centered diets. That is keeper caution about what the ingredient lists show — not product-specific evidence about any particular product’s dose or exposure — so assess products by their own ingredient lists, and keep the diet varied rather than pellet-centered.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); CSJ food guide (https://crabstreetjournal.org/blog/hermit-crab-food-guide/)

Q9. Do they need both fresh water and salt water?

Yes — two separate pools: one freshwater, one saltwater made with marine aquarium salt (such as Instant Ocean). Table salt and freshwater-aquarium salt are not substitutes. Condition your tap water according to the product’s own instructions — conditioning products differ, and a product that dechlorinates does not necessarily remove heavy metals, while others bind or detoxify specified contaminants. Treat for chlorine/chloramine as applicable and follow the label.

Mix marine salt per the product’s own package instructions. Instant Ocean’s own product page says to mix with ordinary dechlorinated tap or purified water — ½ cup per US gallon for small quantities — stir vigorously, aerate, then measure the specific gravity (recommended range 1.020–1.024 at 77 °F), adding salt or dechlorinated water to adjust. Instant Ocean’s own usage note: never mix salt in an aquarium containing animals — mix outside occupied pools, and only return animals after the salt is completely mixed, aerated, and adjusted. These figures are the product’s mixing recipe, not species-specific evidence of optimal salinity for Purple Pinchers.

Each pool should be deep enough for your largest crab to fully submerge, and every pool needs something the crabs can climb to get back out — a crab trapped underwater can drown.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); LHCOS Habitat Standards (https://lhcos.org/hermit-crab-care-education-standards/habitat-standards-for-ethical-hermit-crab-care/); CSJ new-owner checklist (https://crabstreetjournal.org/blog/the-newbies-guide-to-hermit-crabs/); Instant Ocean Sea Salt product page (https://www.instantocean.com/products/sea-salt-mixes/sea-salt) — read directly 2026-10-04

Q10. My crab buried itself and disappeared. Is it molting? Should I dig it up?

Most likely it’s molting — or de-stressing, which new store-bought crabs often do for days or weeks. Either way: do not dig it up. Disturbing a buried crab can injure or kill it. (The accepted exceptions are emergencies like flooding or a bacterial bloom, where leaving it buried is worse.) Molts can last weeks to a couple of months depending on the crab’s size. Keep food and water out for the crabs still above ground, and wait.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); HCA molt-or-dying guide (https://www.hermitcrabassociation.com/phpBB/viewtopic.php?t=92522)

Q11. How can I tell if my crab is molting or dead?

Smell is a warning sign, not a diagnosis. A deceased crab typically droops out of its shell and, after a day or two, can give off a strong rotting-fish odor — but sometimes there is no smell, and food or substrate can smell bad on its own. A molted exoskeleton looks exactly like a limp, lifeless crab, which fools a lot of new owners — but a shed exo is an empty husk (often split or separated from the body), not the animal.

When in doubt: observe without handling, and protect the crab from tankmates (see the surface-molt steps below). An odor warrants checking the things you can check without disturbing the crab — spoiled food, standing water, temperature and humidity readings — since food and habitat problems can smell too. Never discard a crab or dig one up solely because of odor. If you can’t tell, the references’ fallback is to keep the crab safe from tankmates and wait; if you’re genuinely uncertain, ask an experienced keeper for help promptly.

Surface-molt protocol (protect, don’t intervene): a surface molt — molting above ground — can occur even in stable, suitable setups; it is not automatically a sign of bad husbandry. Cover the soft crab with a vented barrier inside the tank — a cut plastic-bottle dome with ventilation holes is the usual keeper-made option — and keep the normal day/night light cycle (CSJ explicitly warns against total darkness). No direct misting of a soft crab, and no standing water around it. Keep the shed exoskeleton with the crab — it will eat it to recover nutrients and harden.

One conditional rule: if the soft crab is somewhere safe and tankmates cannot reach it, leave it in place — handling a soft crab can injure it, and its main danger is interference from tankmates. If the location is unsafe (somewhere the crab will be crushed, flooded, or otherwise harmed), or tankmates can still reach the crab or stay overly interested in it, move it the minimum necessary into a secure ventilated container inside the main habitat (see the soft-crab protocol in Q12): lift it with a spoon or scoop together with the substrate under its body, never touching the soft body, and set it down with its shed exoskeleton — then protect it in place as above.

Limits of a bottle barrier: a barrier pressed into the substrate is not guaranteed protection — tankmates can dig underneath it. Do not push a barrier blindly through occupied substrate to the tank bottom — you could crush or collapse a buried molter’s molt cave.

Rejoining the group: a soft crab can return to the colony only once its exoskeleton has hardened and its strength has recovered — movement and eating alone are not enough to end protection, and there is no fixed recovery deadline.

How this fits with the naked-crab emergency (Q12): a surface molter is soft and vulnerable — but usually still in its shell, so it gets the protect-in-place treatment above, not the shell-cup used for firm naked crabs. The two procedures are for different situations (soft vs. firm).

Sources: HCA molt-or-dying guide (https://www.hermitcrabassociation.com/phpBB/viewtopic.php?t=92522) — accessed 2026-10-03; CSJ molt-or-death guide (https://crabstreetjournal.org/blog/is-my-hermit-crab-dead-or-molting/) — accessed 2026-10-04; CSJ surface-molt guide (https://crabstreetjournal.org/blog/surface-molts/) — accessed 2026-10-04; CSJ out-of-shell emergency guide (https://crabstreetjournal.org/blog/help-my-hermit-crab-has-left-its-shell-what-do-i-do/) — accessed 2026-10-04

Q12. My crab is out of its shell (naked)! What do I do?

Treat it as an emergency — a naked crab’s soft abdomen is exposed to injury and drying, and a crab that stays shell-less is at serious risk. But the right response depends on whether the crab is firm or soft, so look first without touching its abdomen:

If it still hasn’t taken a shell after 30–60 minutes: move the crab to a slightly larger secure isolation container kept at normal heat and humidity. Provide the abandoned shell, several correctly sized natural shells, a small dish of conditioned freshwater, a small dish of marine-grade saltwater, a small amount of varied food, a natural calcium source, and a dark hiding area. Keep the enclosure quiet and limit disturbance. Don’t force-feed, and don’t use honey as a routine emergency treatment — a weak crab may be unable or unwilling to eat right away; stable conditions and protection from injury matter most. If the crab enters a shell, keep observing it in isolation and investigate why it evacuated the original shell before returning it to the colony. If it still refuses shells after extended isolation, ask for help promptly — don’t wait indefinitely. Experienced keepers can help you correct husbandry, but they are not a substitute for veterinary assessment.

Returning to the colony: once the crab is back in a shell, its exoskeleton has hardened, and its strength has recovered — and you’ve fixed whatever drove it out (shell shortage, a fight, bad temperature or humidity) — it can rejoin the group. Movement and eating alone are not enough; protection must not end before hardening, and there is no fixed recovery deadline — it varies by crab and molt. Watch it closely for the first day — a crab that drops its shell again needs the emergency steps repeated, not an immediate return. Don’t delay the emergency to boil shells (rinse with conditioned water instead, and check no small crab is hiding inside).

When to escalate to professional help: CSJ’s current guide says to seek a qualified exotic-animal or aquatic veterinarian, university veterinary service, or invertebrate diagnostic lab when available if the abdomen is torn, bleeding, or visibly deteriorating; the crab repeatedly leaves every shell it enters; there is a strong foul odor unrelated to normal molting; several crabs become shell-less or ill at the same time; there has been pesticide or chemical exposure; there is severe limb loss or other trauma; or the crab remains unresponsive and won’t take a shell despite stable supportive care. Don’t apply medications, oils, herbal preparations, or household products to the exposed abdomen unless a qualified professional directs it.

Where the references disagree: HCA’s naked-crab guidance is a 2021 forum reply (t=125146) reproducing attributed guidance; its last-resort manual step is described as positioning the shell behind the crab and lightly tapping its head so it backs in — not pushing the abdomen into the shell. CSJ’s emergency guide explicitly forbids forcing a crab into a shell, warning it can cause injury. This guide uses voluntary shell entry: offer suitable shells and let the crab enter on its own. It does not teach manual re-shelling. This is a conservative editorial approach based on keeper guidance, not a claim of scientific consensus or controlled validation.

Sources: CSJ “Hermit Crab Out of Shell? What to Do Right Now (Emergency Guide)” (https://crabstreetjournal.org/blog/help-my-hermit-crab-has-left-its-shell-what-do-i-do/) — accessed 2026-10-04; HCA “MOLTING OUT OF SHELL” (forum thread reproducing the naked-crab guide) (https://www.hermitcrabassociation.com/phpBB/viewtopic.php?t=125146) — accessed 2026-10-04

Q13. Can I take my crabs out and handle them?

Think of hermit crabs as observation pets, not handling pets. Brief handling is fine when there’s a reason — a health check, an emergency, moving tanks, or an ID photo — but routine handling for play or entertainment should be avoided. The risks are falls, injury, dehydration, and respiratory stress: dry room air can dry their gill surfaces, and the commonly cited 70–85% humidity band is care guidance, not proof of a sharp biological cutoff at any specific percentage. Set up an interesting tank and enjoy watching them in it.

Sources: CSJ hands-off article (https://crabstreetjournal.org/blog/hermit-crabs-a-hands-off-pet/); CSJ anatomy page (https://crabstreetjournal.org/blog/anatomy-of-land-hermit-crabs/)

Q14. Are hermit crabs nocturnal? Mine hide all day.

They’re mostly nocturnal — most active in the evening and at night — but not strictly so; some individuals come out during the day, especially in the morning and evening. New crabs often bury themselves for days or weeks to de-stress, which is normal. Crabs that feel secure, with plenty of hiding spots and climbing enrichment, tend to show themselves more.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); HCA Purple Pincher species sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?t=92452)

Q15. My crabs seem to be fighting. What should I do?

If a crab is injured or being dangerously targeted, protect it first — prevent further contact before working through any resource checks. The safest separation depends on the situation: shield the victim, or temporarily move the aggressor aside (CSJ’s shellless guide explicitly allows moving an aggressor aside while correcting shell access and other resource shortages). A crab left shell-less by a fight needs the naked-crab emergency steps in Q12, not just separation.

Then check the resources: CSJ’s aggression guide links many aggression problems to stress, competition, and resource shortages — enough shells (see Q6), enough protein-rich food, and enough space. That shortage link is attributed keeper guidance, not settled biology; fix the underlying shortage in all cases, but treat mechanism claims as keeper theory rather than proven cause (see the attribution note at the end of this answer).

What aggression actually looks like: the references describe specific observable events rather than a general “aggression” vocabulary. CSJ’s aggression guide lists the warning signs of true aggression: repeated harassment that doesn’t stop, repeated targeting of the same crab, prolonged pinching, dragging another crab, forced shell eviction attempts, repeated shell jacking, cornering or trapping another crab, blocking access to food or water, and attacking a weak, injured, or molting crab. HCA’s basic sheet describes a crab short on shell choices forcing a tankmate out of its shell to steal it, and HCA’s attacked-crab guide describes crabs found with missing limbs after an attack. Chirping: CSJ states plainly that chirping “should not be treated as a standalone sign of aggression” — what matters is context. Crabs chirp during handling, restraint, shell changes, startle responses, and routine activity as well as conflict, so chirping alone, without any of the physical signs above, does not establish that a fight is happening.

Soft or molting exception: do not pick up and move an injured crab that is soft or actively molting — handling can injure it further. Protect it in place with a vented barrier (the same protect-in-place approach as a surface molter, Q11). But do not leave it in danger while waiting for it to harden: if the soft crab is still being attacked, is somewhere it will be crushed or flooded, or tankmates can still reach it, move it the minimum necessary — lift it with a spoon or scoop together with the substrate under its body, never touching the soft abdomen — to a secure ventilated container inside the main habitat, following the soft-crab protocol in Q12 (supporting substrate, shed exoskeleton, essentials positioned, no standing water touching the crab, no direct misting, stable heat and humidity, normal light cycle). It can rejoin the group only once its exoskeleton has hardened and its strength has recovered — movement and eating alone are not enough, and there is no fixed recovery deadline.

On “molters attract attacks”: keepers have long claimed molters smell like food to tankmates, but CSJ’s current surface-molt guide does not endorse that claim — it notes that post-molt male attention toward females is frequently misidentified as aggression when it is actually reproductive behavior. Whether husbandry failure “usually” causes attacks is also an attributed keeper theory, not settled biology; the actual hazard is that a soft crab is vulnerable to interference and injury.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457) — accessed 2026-10-03; HCA attacked-crab guide (https://hermitcrabassociation.com/phpBB/viewtopic.php?t=92528) — accessed 2026-10-04; CSJ aggression guide, “How to Tell If Hermit Crabs Are Fighting” (https://crabstreetjournal.org/blog/identifying-and-addressing-aggression-in-hermit-crabs/) — accessed 2026-10-04; CSJ surface-molt guide (https://crabstreetjournal.org/blog/surface-molts/) — accessed 2026-10-04; CSJ out-of-shell emergency guide (https://crabstreetjournal.org/blog/help-my-hermit-crab-has-left-its-shell-what-do-i-do/) — accessed 2026-10-04

Q16. Why does my tank smell, and how do I deal with mold?

An odor warrants checking accessible food and habitat — it is not a death diagnosis, and not a bacterial-bloom diagnosis. An odor can have multiple causes — spoiled food, wet or decaying substrate, dirty pools, or off habitat readings — so check the things you can check without disturbing buried crabs: remove uneaten fresh food daily and inspect accessible food, pools, temperature and humidity readings, and other visible problems. (Note: wet calcium sand can also smell bad on its own, which is a substrate problem, not a crab problem.) As for mold: in a warm, humid tank full of organic matter, some mold is pretty much unavoidable — but that is not a guarantee it is harmless, and the references’ reassurances are keeper experience, not published study. Mold is also not automatically a crisis: distinguish a small spot from an emergency.

Minor mold — spot treatment, not a teardown. A spot of mold on food or a piece of decor is routine: pull the item and clean or replace it — replacing a moldy item is the simplest safe choice. Verified material cautions: never boil rocks — CSJ warns explicitly that “some rocks can crack, pop, or explode when heated” — do not heat plastics, and use no soap, scented cleaners, essential oils, or household chemicals on anything going back into the habitat; if you boil shells, check each one first so no crab is hiding inside, and never boil an occupied shell. Do not dig through the substrate or tear the tank down for ordinary minor mold — CSJ’s cleaning guide says a total teardown is not part of normal care and disrupts stable substrate, microorganisms, humidity, and the animals.

Serious contamination — different response. CSJ’s cleaning guide lists the genuine teardown emergencies: flooding of the substrate, a bacterial bloom, a severe mold problem (mold spread extensively through the substrate, not a spot on one item), insect infestation, parasite or disease concern, or a dead animal not found quickly. HCA’s substrate guidance separately names flooding and bacterial blooms as the rare accepted reasons to dig up even buried molters — the two sources’ teardown triggers are recorded separately in the research notes rather than blended into one list. In these cases, discard and replace the contaminated substrate rather than trying to salvage it — and prepare temporary heated, humid, escape-proof housing for the crabs first, using it for the shortest reasonable time. Don’t diagnose a bacterial bloom from odor alone, and don’t spray saltwater around the tank as a routine mold fix. Note: CSJ’s cleaning guide describes temporary housing and cleaning — it is not a dedicated procedure for safely excavating occupied molt chambers, so a suspected emergency relocation needs experienced or professional help, not an improvised extraction.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457) — accessed 2026-10-03; HCA substrate guide (https://hermitcrabassociation.com/phpBB/viewtopic.php?p=852645) — accessed 2026-10-03; CSJ tank-cleaning guide (https://crabstreetjournal.org/blog/how-do-i-clean-my-hermit-crab-tank-crabitat/) — accessed 2026-10-04

Q17. What wood and decorations are safe?

Standard safe climbing woods include cholla wood, cork bark, mopani, and driftwood; keeper moderators also list oak, aspen, and pinecones. Yard-collected wood needs positive identification of the species plus a safe-material reference before it goes in the tank — “pesticide-free” alone does not make every yard wood safe. “Driftwood” describes where a piece came from, not a safety guarantee: unknown coatings, treatments, contamination, and decay still matter. If you’re not sure what a wood is, keep it out of a beginner tank. Avoid cedar — its oils are harmful to hermit crabs — and steer clear of pine branches and large amounts of pine (strong volatile oils), plus anything painted, dyed, or pressure-treated. Boiling or baking does not make an unsafe wood safe — heat treatment is for killing hitchhikers, bacteria, and mold on materials that are already safe, not for detoxifying toxic ones.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); CSJ tank-cleaning guide (https://crabstreetjournal.org/blog/how-do-i-clean-my-hermit-crab-tank-crabitat/) — accessed 2026-10-04; HCA wood thread (https://www.hermitcrabassociation.com/phpBB/viewtopic.php?t=109532)

Q18. I’m upgrading to a bigger tank but some crabs are buried. What now?

If the upgrade is optional, wait — let the buried crabs finish molting and come up on their own before moving anything. That is the references’ answer for voluntary upgrades. Moving substrate with molters buried in it is not an endorsed procedure; it shows up only as forum anecdote for forced moves (like moving house), with explicit warnings that a collapsed molt cave can suffocate the crab. An emergency relocation is a different, higher-risk situation — don’t treat it as routine tank maintenance.

Sources: HCA Basic Care Sheet (https://hermitcrabassociation.com/phpBB/viewtopic.php?f=51&t=92457); HCA substrate guide (https://hermitcrabassociation.com/phpBB/viewtopic.php?p=852645)

Q19. Do I need special lighting?

Give them a steady day/night rhythm — about 12 hours of light and 12 of dark — with true darkness at night. A conservative beginner setup: ambient room light in a bright room, or a simple low-heat light on a timer in a dark corner. Keep direct sunlight off the tank (overheating risk). If you use any night lighting, remember that colored bulbs are still light, not darkness — the dark period should be truly dark. UVB light has not been shown necessary for Coenobita calcium metabolism, molting, or survival — phrase that as a lack of established necessity, not proof it has no benefit; don’t treat UVB as a beginner requirement.

Heat-lamp recommendations differ among keeper references. For this beginner guide, use the wall-heater approach described in Q5 and follow the actual product instructions; this does not establish that every other heating system is unsuitable.

Sources: CSJ new-owner checklist (https://crabstreetjournal.org/blog/the-newbies-guide-to-hermit-crabs/); CSJ UVB article (https://crabstreetjournal.org/blog/is-uv-light-necessary-for-land-hermit-crabs/).