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Hermit Crab Glossary - Understanding The Lingo

If you are a member of online Hermit Crab forums, Facebook groups or read crab care blogs online, you may come across some words related to the hermie world that you may not understand the exact meaning of.

Perhaps an experienced owner is talking about something using the hermie lingo, maybe you are too shy or embarrased to ask what they mean. That's cool, we got you!

Below we go over some of the most commonly used terms and shortened abbreviations for commonly used words in the wonderful world of Hermit Crabs.


Arthropod - Any of a phylum of invertebrate animals (as insects, arachnids, and crustaceans) having a segmented body, jointed limbs, and a shell of chitin that is shed periodically

Air Pump - A pump used to push air through the airline and into the air stones or sponge filter causing the bubbling effect

Air Stones - Small compacted stones that air is blown through to cause bubbles in the pools

Additives - Substances added to foods to prolong shelf life and enhance flavour

Above Sub Line - A term used for your heat source placement, it must be placed above the substrate line in order to not dry out or burn the substrate

Air Line - A plastic Hollow hose that connects to your air pump and air stones/sponge filter to push air through to create bubbles

Aquatic Plant Matter - Plants that are found in the ocean such as various seaweeds

Antennae - A pair of long, thin sensory appendages on the heads of insects, crustaceans, and some other arthropods


Bubbler - This is what is placed into the pools to create the bubble effect

Beta-carotene - A pigment found in plants that gives them their natural colour

Breeders - Owners who have successfully bred Captive Hermit Crabs

Black Tips - The black nails on the end of a Hermit Crabs walking legs, a clear sign they have been moulting


Caliper - A digital device used to measure the opening size of shells

Coenobita - Hermit Crab species

Coenobita Variabilis - The Australian Land Hermit Crab species

Crabitat - Hermit Crab Tank, Crab Habitat

Clean Up Crew - Insects that are placed into your tank to keep it clean by consuming poo, old food, bacteria etc. Usually Springtails or Isopods

Chelipeds - The Hermit Crabs large claws at the front of their body

Check Valve - A two way valve placed into your airline to stop water from moving up the line and back into the airpump should there be a failure

Coir Peat - A natural fibre extrated from the outer husk of the coconut, used to mix into the sand for the substrate

Calcium Sand - A white sand that sets hard when it comes into contact with water, this should never be used inside your tank

CBB - Captive Bred Babies

Chitin - A polysaccharide which makes up the cell walls of fungi and exoskeleton of insects

Carotenoids - The pigments found in plants, algae and bacteria that give them those bright yellow, orange, and red colours

Captive Breeding - Breeding Hermit Crabs in captivity at home

CSJ - Crab Street Journal (Hermit Crab blog)

Commercial Foods - Hermit Crab Labelled foods found at pet stores or Aquariums

Calibrate - Checking a hygrometers accuracy

Coffee Jar Method - A makeshift kreisel tank made using coffee jars to raise spawned Zoea

Changing Pants - Changing Shells

Crustaceans - Invertebrates with a hard exoskeleton

Colour Enhancer - Foods that can enhance the colour of your Hermit Crabs exoskeleton, usually from Carotenoids

Crab Con - A Hermit Crab conference based in the US, also virtually worldwide

Chirping - A noise that a Hermit Crab makes when they are extremely stressed


Distress - When a new Hermit Crab digs down into the substrate and stays there for weeks on end to calm down after their stressful ordeal

D - Shape - The opening shape of a Hermit Crabs shell, has a letter D shape appearance

Dig Down - When a Hermit Crab digs down into the substrate

Dropping Limbs - When a Hermit Crab has lossed a limb (leg or claw)

Deep Pools - Pools that are deep enough for a large crab to fully submerge


Exo - Short for Exoskeleton

Exoskeleton - A hard outer covering that protects the body of Hermit Crabs

Enrichment - The action of improving the quality of your crabs life by placing plants, activities etc into the tank. Environmental Enrichment

EE - Short for Eco Earth, similar to our coir peat, but is usually used overseas in the US


Fish Egg Crate - A hard plastic crate like material, often used for pool ladders or climbing walls

Fresh Pool - The pool in a crabitat that contains fresh, treated water

Foraged - Searching for foods, Hermit Crabs will forage in the wild for food

Food Mites - Mites that are solely there for the foods in your tank, they are no harm to your Hermit Crabs


Gastropod - A type of mollusc, a snail.

Gonopores - The female Hermit Crabs sex organs

Greensand - A highly nutritious Marine sediment fed to Hermit Crabs as a supplement

Gravid - A female Hermit Crab carrying eggs

Gutter Guard - A plastic mesh type material found at most hardware stores that is commonly used in pools as a climbing ramp


Hygrometer - A gauge that measures humidity levels

Hermit House - Non-profit charity supporting Captive Breeding of Hermit Crabs

Hideout - A safe and dark place for a Hermit Crab to hide

HCA - Hermit Crab Association

Heat Mat - A black electrical mat that produces heat when plugged in and placed against the outside of a tank

Heat Cord - A long thick electrical cord that produces heat when plugged in and tapped to the outside of a tank

Hermie - Short name for Hermit Crab


Iso - Short for Isolation

Isolation - Housing a crab alone, usually in a smaller setup, container or mug

Insect Frass - Black Solider Fly Larave poo

Internal Filter - A water filter that is placed inside the pool to filter the water

Insulation - A heatproof source such as car winsheild protector, foam, foil etc and placed over the top of your heat source to keep the heat going back into the tank

Insulation Tape - A silver heat proof tape that can be safely placed over heat sources to stick them to the tank without melting

Instant Ocean - A brand of marine salt commonly found in the US


Jumbo - Refers to a very large Hermit Crab that is in a shell opening of 3"+

Juvenile - A young baby Hermit Crab


Kreisel - A specially built tank made up of marine water and constant water motion to raise zoea in

Krabooz - A commonly sold Hermit Crab brand in Australia, not suitable for Hermit Crabs


LHCOS - Land Hermit Crab Owners Society

Leaf Litter - Leaves and plant materials often found on the ground in the wild that Hermit Crabs consume

Lipids - A form of Fatty Acids


Megas - Short for Megalopae

Megalopae - The third stage of a Hermit Crabs life cycle, they appear as tiny translucent lobsters

Modified Gills - Gills on a Hermit Crab that are modified to allow them to breathe on land

Marine Hermit Crab - A species of Hermit Crab that solely lives in ocean water and cannot survive on land

Moult Sac - A dark grey/black bulge on the side of a Hermit Crabs abdomen, used to store food and water for their moult

Moult Cave - A cave beneath the sand that a crab has dug for themselves to begin their moult

Moult - When a Hermit Crab sheds their exoskeleton in order to grow

Moult Camp - When a Hermit Crab is under the surface, moulting

Marine Salt - A specific sea salt for marine creatures, carries all of the necessary vitamins and minerals

Mixes - Handmade Hermit Crab foods


Naked - A Hermit Crab without a shell

Nocturnal - Active at night time

Novelty Shells - Shells that have been painted, toxic to Hermit Crabs


Oval - Shape - The opening shape of a Hermit Crabs shell, has an oval appearance

Omnivore - An animal that eats both plants and animal proteins


PPS - Post Purchase Syndrome

Prime - A water conditioner

Pleopods - Feathery appendages attached to the females abdomen to hold her eggs

PP - Short for Purple Pincher

Purple Pincher - A nickname for the Hermit Crab species Coenobita Clypeatus, known for its large purple cheliped

Pellets - Pet store foods that have been pressed into a pellet, not appropriate for Hermit Crabs as a diet

Perspex - A thick acrylic sheet

Pesticides - A substance or mixture to kill, prevent or repell pests

Preservatives - A substance used to preserve a foods shelf life

Playsand - Sand that has been pre washed, treated and bagged up for purchase

Prey Animal - Any animal that serves as a food source for another animal

Pants - A Hermit Crabs shell

Post Purchase Syndrome - What a shop brought Hermit Crab goes through once they have been purchased and arrive to a new tank, a very stressful situation for them



Refractometer - A refractometer is an optical instrument that is used to determine the refractive index of a substance, measuring how light is bent as it moves through the substance. Often used to calculate the salinity of the salt water pool

Round - Shape The opening shape of a Hermit Crabs shell, has a round circle appearance

Ratio - Shows how many times one number contains another. For example, 8 parts sand to 1 part of coir peat is an 8:1 ratio

Rescues - A Hermit Crab that has been rescued from another owner who housed them in inappropriate setups

Reptile Bedding - A tanbark type of substrate that is not appropriate for Hermit Crabs


Sub - Short for Substrate

Substrate - The sand/coir peat mixture that is placed into the bottom of the tank

Shell Jacking - When one crab attempts to steal another crabs shell

Shell Shop - An area of shells gathered together for your crabs to choose from

Shell Alteration - When a Hermit Crab pulls parts of their shell off to make it fit better and be more comfortable

Shell Size - Refers to the opening of the shell, not the actual shell itself

Surface Moult - When a Hermit Crab attemps their moult above the sand out in the open

Sponge Filter - A filter with an external sponge

Spawning - When a Hermit Crab releases its eggs into the salt pool, zoea are spawned

Strawberries - A nickname for the Hermit Crab species Coenobita Perlatus, known for its bright red and orange colours

Supplements - Specialist foods added to a crabs diet to complete their dietary needs

Sphagnum Moss - A dried moss that is safe for Hermit Crabs and can be dampened and added into the crabitat to aid in humidity

Salt Pool - The pool in a crabitat that contains salted, treated water

Sexing - Checking the gender of your Hermit Crab

Sizing Up - When a Hermit Crab checks the opening size of a new shell to see if it will fit them

Shell Grit - finely found ground shells, and miniature shells, a great source of Calcium

Safe Foods - Foods that can be safely consumed by Hermit Crabs

Sand Castle Consistency - Substrate that holds its shape when you push your finger into it

Straw Test - When you push a straw into the substrate, up against the glass to check for floods or substrate consistency


Topper - A second tank placed on top of your current tank

Thermostat - A plug in device known for detecting temperature changes, and keeping them at consistent levels with the tank

Transition Tank - A small tank with low substrate that has been set up for shelled Megalopae who are moving from water to land for the first time

Too Land - When a shelled Megalopae moves from their water to land for the very first time

Turbo - The name of a top shaped shell

Terrestrial - A living organism that grows or lives on land


UTH - Short for Under Tank Heater (although they should never be placed under a Hermit Crab tank)

Under - When Hermit Crabs are under the substrate

Unsafe Foods - Foods that are toxic to Hermit Crabs


Vacation Food - A long lasting food mix with specific ingredients to make it last longer in the tank without moulding


Wattage - An amount of electrical power

Whelk - Whelks are any of several carnivorous sea snail species with a swirling, tapered shell

Worm Castings - Worm Poo

Water Conditioner - A liquid used to remove Chlorine, Ammonia, Chloramine, Nitrites and Nirates from tap water

Welfare Check - Checking a Hermit Crab for sickness, disease, limb loss, discolouration etc




Zoea - The larvae that hatches from a Hermit Crabs eggs, the very first stage of the life cycle

Zeaxanthin - Is a fat soluble antioxidant carotenoid

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