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50 Hermit Crab FAQ's

How long is too long in the pool?

There is no set amount of how long your crabby can be in the pools, as long as you have a safe way in and out, they will leave when they are ready. If you have no way out of the pool and you find a hermie in there, remove them and add a climbing object so they can leave. If you find a naked crab in your pool, remove it immediately and follow the naked crab protocol.

Has my Hermit Crab moulted?

Usually a clear sign of a freshly moulted Hermit Crab is their appearance. They will usually have hairy legs and sharp black finger nails on the end of their legs. If your crab has been down for weeks-months on end and comes back up looking extra hairy and with fresh black tips, it's safe to say they have had a successful moult!

Why is my Hermit Crab naked?

Hermit Crabs will drop their shell when they are stressed or sick. This usually happens when a crab is housed in an inappropriate setup. Other reasons a crab may go naked include lack of appropriate shells, a broken shell, a shell jacking. Isolate the crab immediately and follow the naked crab protocol here https://www.happyhermie.com.au/post/naked-hermit-crab-what-to-do

Is my Hermit Crab dead?

It can often be difficult to distinguish between a dead crab and a surface moulting crab. A pretty clear indicator of a crab that has passed away is it will smell, there will be no movement when touched and when picked up by the shell it will fall out of its shell. A surface moulter will twitch slightly if touched and when you pick up their shell, they will not fall out.

If you are still unsure, isolate the crab and if if has not dropped its exoskeleton or moved within a week, it is safe to say it has probably passed away.

What is the correct temperature and humidity ranges?

Australian Hermit Crabs prefer a temperature range of 26-32.c degrees with 28.c being optimal. They also need humidity between 70-85%. Too low and they will start to suffocate. Too high isn't so much an issue, but can be aid in mould growth and condensation.

Are my Hermit crabs happy?

If you provide the correct environment, filled with enrichment, deep substrate, deep pools, correct tank readings, healthy foods, activities and friends, your Hermit Crab will be happy and living their best captive life. Another sign that your crabs are truly happy, comfortable and content is that they will start breeding. This however is only possible with males and sexually matured females in the tank and an absolutely perfect environment.

Is it okay for Hermit crabs to be on their wheel all day?

Absolutely! In the wild, Hermit Crabs travel multiple kilometres a day, they love walking! Being on the wheel will mimmick this natural instinct to travel.

How can I bring my temperature up?

Try adding more heat sources, blankets, insulation, and making sure the tank is sealed.

How can I bring my humidity down?

When the tank temperature is too low, humidity will sky-rocket. Bring your temperature upto 28.c and your humidity will start to level out. Alternatively, you can also add dry sphagnum moss to soak up excess humidity.

Why is my tank so cold?

A cold tank is never good, check that you have the correct Wattage on your tank. Anything below 20W will not do any good.

Also check that your heat mats are operating properly. If they are not, they may need to be replaced.

You should also add insulation to your heat sources, this can save upto 20% of your heat.

Do hermit crabs only change shells when moulting?

No, your Hermit Crab will change shells when they are ready and at any stage during their cycle. Not just before or after a moult. Sometimes they can carry the same shell for years before changing.

Why won't my crab change shells?

Hermit Crabs will change their shells when they are good and ready. Especially if you have all of the appropriate shells in the correct sizes. Sometimes they won't change shells if the tank conditions are not suitable, or the shells on offer are not the correct size or shape. Hermit Crabs prefer to change shells when they feel safe and secure in an appropriate environment.

Is it okay to handle my Hermit crabs?

No. Please avoid handling your Hermit crabs or removing them from the tank. This causes them a great deal of stress, and they will struggle to breathe in conditions that are outside of their tank.

Some times handling is needed such as finding a naked crab, a surface moulting crab, a shell jacking attempt, during an aggressive fight, during sexing, shell measuring or moving them to another tank. You can read more about handling here https://www.happyhermie.com.au/post/hermit-crabs-the-hands-off-pet

How can I tell if my crab is a boy or girl?

Female Hermit Crabs have sex organs known as Gonopores. Two little dots located underneath the 3rd pair of legs. They also have pleopods on their abdomen to hold their eggs. Males do not have either of these. If you hold your crab upside down by its shell, wait for it to come out of its shell slightly and check for Gonopores. You can read more about gender here https://www.happyhermie.com.au/post/is-my-hermit-crab-a-boy-or-a-girl

How do I stop my hammocks and Driftwood from moulding?

To prevent mould, soak your hammocks and Driftwood in salted water and air dry in the sun. To remove mouldy decor, scrub the mould off in hot soapy water and soak in salted water and air dry in the sun.

Repeat as necessary.

Are live plants okay in my crabitat?

We recommend staying away from live plants with a root system. These will grow into the substrate and take up precious moulting space. If you do choose to use live plants, we suggest going with Air Plants or a Chia garden.

How often do I change the tank substrate?

If done right the first time, never.

If there is an emergency such as a flood or bug infestation, you will need to remove all of the substrate and start again.

What can I use to clean a second hand tank?

You should always clean a second hand tank before using. We recommend using water with diluted vinegar and a rag or paper towel. Then give it a rinse down with plain water.

Can I use metal in my tank?

Metal will rust in high humidity environments, we suggest trying to keep as much metal out of your tank as possible.

What glues are safe?

Glues that you can use in your tank are Aquarium Sealant or a hot glue gun.

How often should I feed my Hermit crabs?

Hermit Crabs should have food readily available at all times. Change their dry foods out every few days or when it begins to mould or the bowl is empty. Remove fresh foods every day before they mould to much.

Do I need to wash the substrate before putting it in the tank?

No. You should only be using sand that has come in a sealed bag and has been prewashed. There is no need to wash it again.

I haven't seen my crab in awhile, should I dig for them?

Please never dig for your crabs. They will come back up when they ready. The only time you should dig for your crabs is during an emergency such as flooding, bug infestation or if you are relocating and have no choice. Digging up a crab that could be moulting is incredibly dangerous for them and can cause death or limb loss.

How long will my Hermit Crab stay under the sand for?

There is no set time for this. They can stay down for a few days or upwards of 6+ months. That is entirely upto the crab. They dig down for moulting, distressing or just to pass the time and dig tunnels.

Do I need to bathe my Hermit Crab?

No, you do not need to bathe your crabs. If you have deep pools available, they will bathe themselves when they feel like it.

How do I hang things inside my tank?

We recommend using suction cups or heavy duty plastic hooks that are removable. You can also glue decorations to the tank if needed.

Can hermit crabs live alone?

Yes, but they prefer not too. Hermit Crabs live in large colonies in the wild and they thoroughly enjoy the company of friends. They can and do get lonely if they are housed alone.

Where is the best place to put my thermometer/hygrometer?

For the most accurate reading, place your thermometer/hygrometer in the middle of the tank 2-3cm above the substrate.

What is a clean up crew, and do I need one?

Clean up crews are not a necessity, they are just there to help keep your tank clean of old food, poo and any bacteria. Cleanup crews usually include Springtails and Isopods.

How big should my tank be?

One hermit crab needs atleast 38L worth of space inside the tank. And because you should house atleast 2 crabs together, you will need a 76L tank minimum for 2 crabs.

Why is my crab pacing back and forth along the front of the tank?

Your Hermit Crab may be bored. Make sure you have enough enrichment in your tank and activities to keep them busy and entertained.

Are painted shells okay?

No, although they are pretty to look at, unfortunately painted shells are toxic to Hermit Crabs. The paint used to paint the shells is toxic if consumed by the crab. If your crab changes out of a painted shell it is important to remove that shell and bin it. You cannot safely remove the paint and reuse the shell.

Why can't I see any holes in the sub, only mounds of sand, is my crab under the sand mound?

When crabs dig tunnels, they will push the sand back up behind them. This is usually why you see a mound of sand. Sometimes they will make very clear holes to the entrance of their tunnels. You can never really know exactly where a crab is under the substrate, but it is best to leave them be.

How often do I need to change their water?

No bubblers (still water) - every 48 hours

Bubblers - every 7 days

Filters - every 2-4 months

Can I use a heat lamp in my tank?

It is recommended to stay away from heat lamps, they can cause hot spots within the tank and dry out your substrate. Heat sources should be on the outside of the tank (heat mats and heat cords)

Why are they called Under Tank Heaters (UTH) if we can't put them under the tank?

Under Tank Heaters are usually used for reptile tanks where it is okay to put them under the sand. Hermit Crabs however, dig down into the substrate to moult so they need a nice cool environment that is moist. If you place the heat mat under the tank, you will dry out the substrate and possibly cook moulting crabs. You only want to heat the air above the substrate.

My crab is constantly changing shells, is that normal?

Some crabs find their perfect shell straight away, while others take a little longer. Considering it pants shopping, you don't buy the very first pair do you! It is totally normal for crabs to continually change shells. They may be testing out what is on offer to see if they like it or not and will often change again to a different shell to give that one a test too. As long as you have the correct sizes available in various shapes, it's upto your crab what they will pick.

Why don't we practice PPS here in Australia?

Post Purchase Syndrome - this is a very stressful time for any new crab that has been brought home for a pet store. Overseas they will usually set up a PPS tank with minimal substrate so that the crab is forced out of a moult and spends their time eating and drinking to refuel before going down for a moult. This doesn't always work tho, as the crab may be forced into a surface moult which is very dangerous. Here in Australia, experts believe that if you add your crabs directly into the correct environment with deep substrate and healthy foods, they will have the chance to safely moult beneath the surface and will eat and drink when they are ready. Obviously this is a free choice, if you decide to follow the PPS method that is entirely your decision.

How can I tell the difference between exoskeleton and a lossed limb?

Sometimes you may find a random leg on top of the sand, of course you wonder did my crab lose a leg or is this just a piece of exoskeleton that has been dug up. Exoskeleton will be empty, where as a lossed limb will be meaty on the inside. The easiest way to tell is by gently crushing the limb between your fingers, if it crumbles to powder, it is exoskeleton. If it does not crumble, it is a meaty limb.

Can I use ocean water in my salt pool?

Yes you can. Just make sure not to bring home any sea critters in your water.

Can I use Cuttlefish Bone I find on the beach in my tank?

Absolutely! Your crabs will love a big chunk of Cuttlefish Bone. This is a great source of Calcium.

Does my tank need airholes for ventilation?

No. Hermit Crabs do not breathe air. They absorb humidity through their modified gills. Your tank should be completely sealed. Air holes will leak out the heat and humidity that your crabs need to survive.

Can I collect shells from the beach for my hermit crabs?

Yes you can (as long as it is legal in your area) we do suggest trying to leave shells at the beach for other sea life to use though. So many shells are harvested every year from the beach, sometimes it can be a struggle for wild Hermit Crabs to find an appropriate home. If you do take shells from the beach please ensure they are 100% empty and you aren't accidently bringing home a marine hermit crab (they will not survive away from the beach) and ensure your shells do not contain holes.

Is it normal for my substrate to dry out?

It is normal for the top layer of substrate to dry out. This is because of the heat within the tank. Usually the top 2-3cm will be dry. It is very important that the substrate underneath is moist and of a sand castle consistency. You can test your substrate by pushing a straw all the way to the bottom of the tank up against the glass, remove the straw and the tunnel should keep its shape. If you substrate is dry all the way to the bottom, it will need to be changed over.

Why are pet store foods bad?

Pet store foods and pellets do not offer a complete diet to cover your crabs entire nurtional needs. When a crab is lacking in a certain nutrional need, they can and will go to great lengths to fill it such as attacking and eating their tank mates. Purchasing dried mixes from home sellers is recommended as these are created from fresh ingredients that will cover their nutrional needs. You should also offer fresh food options when you can.

Is bottled water okay to use for my tank pools?

Yes, you can use bottled water. We cannot guarantee that there is nothing hazardous in bottled water and still recommend using a water conditioner such as Prime. But that choice is entirely upto the owner.

It can get very expensive continually using bottled water and it is a much cheaper option to use tap water and purchase a proper water conditioner.

What is sand castle consistency?

If you poke your finger into the substrate, the hole should keep its shape. Pick up a handful of substrate and mould it into a ball, if it keeps its shape (like a sand castle on the beach) it is sand castle consistency. If it crumbles and does not hold its shape, it is too dry.

Can you overdose the water with Prime if you add more than 1 drop per litre?

No, you cannot overdose the water. Prime water conditioner will treat 1 litre of water with 1 drop, but if you accidently add 10 drops, it will not affect the quality of your water. However, you may use up your Prime alot quicker.

Can I house male and female crabs together?

Absolutely! The chances of your crabs mating and producing zoea is slim (but keep in mind that it is certainly possible)

Keeping males and females together will not cause any extra agreesion.

Can I keep my shells directly on the substrate or do they have to be in a container?

You can put your shells wherever you like. Alot of owners will place their shells into a container to keep them cleaner and prevent them being buried by crabs. If you do keep them on the substrate, you may need to clean them more often and shells may go missing if they have been buried by a crab.




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