#coenobita variabilis

[panicbox]

My Hermit Crab tank! 🦀🐚🍃

All my crabs are very active and moult well. It’s amazing how lively these little guys are when they have the right humidity/temp, a nice area to run around in and plenty of soil to dig in. These little dudes love climbing and burrowing, playing musical shells, submerging themselves completely in their water bowls, Munching on cuttlebone and generally getting into as many crab shenanigans as they possibly can. It’s amazing how entertaining these little troublemakers can be when they aren’t stuffed into a critter keeper or similarly unsuitable habitat.

I ain’t too sure about the sponge though. Some sources say it’s bad because it breeds bacteria, others say it’s important for humidity. I clean it very often and it’s not caused any troubles so far, but if you guys think it’s unnecessary or even harmful I’ll take it out.

[crabstreet]

The lines can be seen clearly seen here. #variabilis #speciesspotlight #hermitcrabs #hermitcrabsofinstagram #crabstigram #instacrab #instahermit #claws #pinchers #coenobita #lhcos #csj #crabstreetjournal #clawlife #shelllife #thoseeyestho #allaboutthatpincher #crabby #crabbysquad #properpetcare

[fbwzoo]

So whats the difference between the hermit crabs you raise, and the full aquatic kind?

If I remember right, the hermit crabs you have are predominantly terrestrial, where as the others are predominantly aquatic, as well as significantly smaller than their terrestrial counter part.

But are they like off shoots of the same species?

I’m not sure of evolutionary development, unfortunately, and that’s more complicated than I can look up right now. I would assume they have a shared ancestor, but possibly several? Wikipedia says “The fossil record of in situ hermit crabs using gastropod shells stretches back to the Late Cretaceous. Before that time, at least some hermit crabs used ammonites' shells instead, as shown by a specimen of Palaeopagurus vandenengeli from the Speeton Clay, Yorkshire, UK from the Lower Cretaceous.“

 But these days, there are over 800 different hermit crab species, and they’re all in the same superfamily, called Paguroidea. There’s 7 families in that group, and 6 of those families are marine/aquatic hermit crabs. The seventh family, Coenobitidae, is all terrestrial hermit crabs, like mine!

The terrestrial hermit crabs include 17 species, including the largest one, the coconut crab! It’s the largest land-dwelling arthropod. We get questions about if anyone’s ever had one on my crab groups sometimes and the consensus is “Fuck no, where would you put it”.

(Photo source)

Coconut crabs are in their own genus, and the rest of the terrestrial crabs are in another. Not all of them are kept as pets, and they live in different parts of the world - there’s only two that live on the west hemisphere. One is Coenobita clypeatus, aka the purple pincher or Caribbean hermit crab. This is also the one that’s mostly found in the pet trade in North America, and most commonly kept as a pet. This is the species all of my crabs are! Also the ones that are available for adoption from Mary at the moment. The other species is Coenobita compressus, the Ecuadorian hermit crab, and they are the other most commonly found in North America’s pet trade. 

All of the other species, to my knowledge, are found in the East hemisphere, largely in the tropics. Australia has one species, Coenobita variabilis. A lot of the others are found in similar areas, on the Indo-Pacific Ocean islands. We have many members in a couple of my hermit crab FB groups that live in the Philippines and other islands that have many of these species - we’re jealous of their crabs & they’re jealous of ours! There’s differences in the color ranges, exoskeleton features, sizes, behavior, types of shells they like, and development between the different species. This site talks about each species & a lot of these characteristics for each!

Also, marine hermit crabs are way more varied than I thought! There’s a family that have matched claws instead of one being bigger, and they hide in wood, rocks, sponges, and other things instead of shells.

There’s two species that have toothed mandibles!! 

I’m glad my hermit crabs don’t have teeth.

Also you mentioned size, and while there are a lot of marine hermit crabs that are much smaller than land hermit crabs can get, there’s a lot that are quite big too! I think it might actually be more normal for marine ones to be bigger than terrestrial ones, with water helping to offset the weight of a big enough shell.

Look at this guy!

(Photo source)

I probably went overboard with this answer, but I hope it’s informative & fun to read! Thank you for the excuse to infodump about hermit crabs! ♥

[hermitharbor]

I notice you (and other ?american? Crab owners) use short hand letters (Es and PPs) for crab species and I was wondering if there's similar shorthand for Coenobita variabilis? Is it just Aussies? Vs?

Yep, they are just called Aussies! :)

[hermitcrabowners-blog]

Australian Crabs (Coenobita Variabilis) Care Guide

Australian Hermit crabs (Coenobita Variabilis) require different habitat conditions than most other crabs. This care sheet was created for people to understand how best to look after their Australian crabs and provide the best habitat possible for them.

Writing Credit: Ash Day

Substrate

Correct substrate is essential for a healthy crab habitat, without correct substrate the crabs will not be able to dig successful tunnels and therefor will not be able to have successful molts. Incorrect substrate may dry out quickly (requiring more misting which may allow the water to build up over time at the bottom of the tank, resulting in a flood) or may not be able to break down waste. Unsuitable substrate includes gravel, straight shell grit, calcium sand, straight coir peat or straight play sand. 

The Australian crabs require an 8:1 ratio of play sand and coir peat brick, do not get confused with coir mulch which is ‘chunky’ and ‘stringy’ in appearance, coir mulch is not suitable for substrate and may harm the crabs. Both play sand and coir peat brick can be picked up at Bunnings.

Following the 8:1 ratio, for every 8 cups of play sand that you put in, you need one cup of soaked coir peat (coir peat expands when wet). 

It is extremely important to mix these two together at the correct ratio, substrate that is just play sand will not be able to hold water well and will get flooded due to the need for extra spraying due to ‘drying out’ or not being able to regulate the humidity. Straight play sand will not be able to hold the moldable shape efficiently that molters and diggers require. Coir peat on its own may cause bacterial blooms and molting problems if the crabs are kept on straight coir for an extended period of time. When play sand and coir peat are mixed together at an 8:1 ratio, these two components of the substrate will balance each other out creating a suitable substrate for the Australian crabs to live and thrive on.

What are the benefits of mixing play sand and coir peat? Having the 8:1 ratio of play sand and coir peat ensures that the:

Waste breaks down efficiently

Mixing the two helps regulate humidity

Less likely to flood or dry out

Holds the mouldable shape for moulters and diggers

Less likely to have mould or a bacterial bloom

Introduces good bacteria to the substrate

Aussie crabs are very active diggers and spend the majority of their time digging about the substrate, the deeper the sub you can provide for them, the happier they will be in their habitat. Ideal depth of substrate is half the tank, this provides suitable digging and molting space for the crabs.

*Additional Substrate Ratio Info – Credit to Emily Coker*

Please note, the ratio guideline goes slightly over the 8:1, but is a very close representation of about how much coir peat to use per bag of play sand. You do not have to follow this formula exactly, this is just a guideline to simplify the amount for you.

The ratio is 8:1 of sand:coir peat, which equates to approximately 20kg play sand:1/3 of 9 litre coir peat brick. That means 8:1 = 1 bag of sand:1/3 brick OR 8:1 = 1:1/3. The 9 litre brick is the Bunnings brand (Coir Power OR Easy Wetta).

8:1 = 20 kg bag of play sand: 1/3 brick of coir peat (3 litres)

8:2 = 20 kg bag of play sand: 2/3 brick of coir peat (6 litres)

8:3 = 20 kg bag of play sand: 1 brick of coir peat (9 litres)

8:4 = 20 kg of play sand: 1 1/3 bricks of coir peat (12 litres)

8:5 = 20 kg of play sand: 1 2/3 bricks of coir peat (15 litres)

8:6 = 20 kg of play sand: 2 bricks of coir peat (18 litres)

8:7 = 20 kg of play sand: 2 1/3 bricks of coir peat (21 litres)

1:1 = 20 kg of play sand: 2 2/3 bricks of coir peat (24 litres) 

As you can see, the end result would go over by about 4 litres of coir peat to be a true 8:1, but the recommendation for those in the US using 5:1 is also slightly over with no harm to the crabs. If you wish to be a little under in coir peat, you would want to use closer to 1/4 brick (which at 1:1 would make you at 18 litres of the 20 needed, and you would be 0.25 litres under at 8:1). That's why we are stressing, once again, that this is a guideline and not exact, but it's a good starting point to help you understand how much is needed. Either 1/3 brick or 1/4 brick for every 20kg bag of sand are acceptable and recommended options.

Here is a quick chart to gauge how much coir peat you will need for different quantities of sand following the 1:1/3 ratio. Note that for the US, it equates to about 1 bag of sand for every 10 gallons of space:

1 bag of sand (20 kg) = 1/3 brick of coir peat (3 litres)

2 bags of sand (40 kg) = 2/3 brick of coir peat (6 litres)

3 bags of sand (60 kg) = 1 brick of coir peat (9 litres)

4 bags of sand (80 kg) = 1 1/3 brick of coir peat (12 litres)

5 bags of sand (100 kg) = 1 2/3 brick of coir peat (15 litres)

6 bags of sand (120 kg) = 2 bricks of coir peat (18 litres)

7 bags of sand (140 kg) = 2 1/3 bricks of coir peat (21 litres)

8 bags of sand (160 kg) = 2 2/3 bricks of coir peat (24 litres)

9 bags of sand (180 kg) = 3 bricks of coir peat (27 litres)

10 bags of sand (200 kg) = 3 1/3 bricks of coir peat (30 litres)

11 bags of sand (220 kg) = 3 2/3 bricks of coir peat (33 litres)

12 bags of sand (240 kg) = 4 bricks of coir peat (36 litres)

13 bags of sand (260 kg) = 4 1/3 bricks of coir peat (39 litres)

14 bags of sand (280 kg) = 4 2/3 bricks of coir peat (42 litres)

15 bags of sand (300 kg) = 5 bricks of coir peat (45 litres)

16 bags of sand (320 kg) = 5 1/3 bricks of coir peat (48 litres)

Humidity & Temperature

Correct humidity and temperature are essential for a the crabs health. If the crab habitat gets too cold the hermit crabs will be at risk of going into a dormant state, risk of streaking increases as does the risk of limb dropping and even death. The correct temperature range is between 26-32C, with 28C being the average temperature you are aiming for in your crabs habitat.

Humidity is extremely important in your habitat as well, hermit crabs need humidity to breathe through their gills. Without the accurate amount of humidity in their tank, the hermit crabs are essentially suffocating. The recommended amount of humidity is an 80% average.

To increase humidity, try adding a pit of damp sphagnum moss, adding bubblers (air stones) to their fresh and salt water pools as well as ensuring the lid is tight. If the lid does not fit properly humidity and temperature can escape, if this is the case try wrapping glad wrap around the tank to seal it until a correctly fitting lid can be found or cut.

Heating & Lighting

As previously mentioned, the habitat should have an average temperature of 28C with a 26-32C range. Heating can play a very important role in keeping that temperature balanced and steady.

UTH (under the tank heaters) are a great way to raise the temperature in your habitat without drying out the substrate and can be bought on eBay or from most pet shops. UTH, however, should actually not be put under the tank as its purpose for the hermit crabs is to warm the air, not the substrate. 

If the substrate is heated up, there will be no way to keep the air at the ideal temperature without ‘cooking’ your hermit crabs that are in the substrate. The substrate provides an ‘escape’ from the conditions if they become too hot, the crabs will bury down into the sub to cool off from the heated air if need be. If the sub is heated up because of the heater being under the tank, you run the risk of actually cooking any molting or digging crabs that may be in the substrate.

The UTH must be stuck onto the side or back of the tank – cannot be on the inside of the tank - (duct tape or packing tape can be used for this), above the substrate line and then the tank must be insulated. Alfoil, cardboard or car sunshades that have being cut to size would work as insulation for the hermit crab tanks. The sun visors can easily be picked up from Harvey Norman or from eBay, cut to size and then stuck with duct tape or packing tape on top of the UTH, ensure that the insulation is covering the sides and the back of the tank, this ensures the hermit crab tank stays heated and is not hugely effected by any temperature drops that may occur due to changing seasons, air con, drafts etc.

Although some people do not believe that lighting can increase colour in the aussie crabs, I (along with many other aussie crabbers) have personally experienced that the correct lighting has increased hermit crab activity as well as giving them a ‘richer’ colour rather than that pale white that is often seen amongst the Australian captive crabs. For this reason, UVB and UVA lighting is recommended for the Australian crabs (as with most other crab species). UVB allows for the absorption of vitamin D in the crabs, as well as making them more active and giving them a ‘richer’ and ‘deeper’ colour.

Fresh & Salt Water

The Australian land hermit crabs (like other land hermit crabs) require one pool of fresh de-chlorinated water and one of de-chlorinated marine grade salt water. The depth of the pool should be deep enough for your largest crab to fully submerge with easy access in and an easy exit out.

In order for the fresh water to be safe for the hermit crabs you should always treat your water prior to use. It may contain traces of chlorine, chloramine, heavy metals or pollutants in the water. These chemicals and such need to be removed from the water. If not removed, the water may actually be harming the hermit crabs.

There are a couple of products in which you can use that can be picked up from most pet shops or from eBay, including:

Prime (Prime is the water conditioner to aim for, but if you can't find Prime then the following brand will do)Please note though, that the following conditioner does not remove Amonia

API (If purchasing API ensure that the API does not contain stress coat, stress coat can cause harm to land hermit crabs and should not be used in their fresh or salt water.)

As for salt water, never use 'Table Salt', 'Aquarium Salt' or 'Hermit Crab Salt' which is lacking in essential minerals that hermit crabs need to live a healthy life. The salt water must be marine grade, salt water products that can be used for the hermit crab pools that provide all the essential minerals for the crabs are:

Red Sea

Instant Ocean

MarineTropic

Oceanic

Other brands of marine grade salt that would be suitable include:

Blue Treasure

Ocean Nature by Aquasonic

Diet

As with the other crab species, any commercial foods containing sugars or preservatives should be avoided with the Aussie crabs as commercial foods are not beneficial to the crabs and are not an adequate diet for them to be on. If commercial foods are fed out there is a higher risk of illness or death to the crabs as it is lacking in essential nutrients and may contain harmful ingredients.

Please see the list of acceptable foods that can be given to hermit crabs, and a list of inedible foods that shouldn’t be given to hermit crabs. It is a very large list with lots of variety to ensure your crabs do not miss out on the best diet available.

To ensure your Aussie crabs are getting a balanced diet make sure you provide sources of calcium, protein, as well as varied vegetables and fruits (always check the edible food list to see if a food item is safe).

Shell Preferences

Australian crabs prefer shells with a ‘d-shape’ opening, shells that Aussie crabs prefer are the:

Nerite Shells

Tonna Shells

Babylonia Shells

Whale eye Shells

Apple Snail Shells

Japanese Land Snail Shells

Murex Trappa Shells

Murex Ramosus Shells

Frog Mouth Shells

Shark Eye Shells

Turbo Shells and Magpie Shells – although these are less common with the Australian Crabs as the openings are ‘round’ rather than D-shaped.

As the hermit crabs grow, they need to exchange their shell for a larger one. You should provide at least 5-6 shells per crab that are similar in structure but slightly larger for the crab to change into. If there are not enough suitable shells for the crabs to choose from,  ‘shell envy’ may occur where the hermit crabs will fight over a specific shell. Adding extra shells to the tank that are suitable should help prevent shell envy from occurring.

(Ensure any shells are boiled before adding them to your tat)

Overcrowding Risks

It is vitally important not to overcrowd your tank, overcrowding can lead to a crab that is molting being dug up as a result of too many crabs digging at the sub in a crowded tank, this can lead to death for the crab that is molting. Overcrowding can also cause stress and lead to increased fights amongst the hermit crabs and not enough adequate space for their exercise needs or to freely move about their tank.

There are a lot of things to consider when deciding on how many crabs should be in one tank, such as hermit crab size, if you plan to upgrade, depth of substrate etc. The general rule to go by though 10 gallons per hermit crab (about 38 litres per crab)

[astronomy-to-zoology]

Australian Land Hermit Crab (Coenobita variabulis)

is a nocturnal species of hermit crab native to Northern Australia. As you may of guessed form its name this species thrives in areas near land and is not exclusively marine. Like most hermit crabs these crustaceans will take shells from gastropods like the shells of Turbo and Bablyonia competition for shells is fierce and hermit crabs are known to use other objects for a shell.

Phylogeny

Animalia-Arthropoda-Crustacea-Malacostraca-Decapoda-Coenobitidae-Coenobita-variabilis

Image Sources: 1,2