HCA: Hermit Crab Association

Hello Everyone!

Recently I got tired of the awful, cramped, boring, and overall bad conditions of my current tank. It’s a measly 10 gallon, the same I bought two years ago! (I know, I know.) Fortunately it’s time for an upgrade. I’m going to begin building a new crabitat for my two wonderful crabs.

This build will be based on the Exo-Terra Small Tall terrarium.



These are the materials I’ve ordered so far.



The terrarium size is 18x18x24....or 33 gallons. Quite an upgrade from my current 10 gallon tank. I picked this verticals terrarium because I am hoping to make two levels. I will use two Penn Plax Lizard Loungers to build the second level.



Hopefully the vertical space will also give me an opportunity to make deep substrate for my largest crab. Currently, the crab is about the size of a tennis ball. He is my longest living crab. I also have another little guy who came from horrible conditions in a pet store. He’s had one or two molts with me.

I also purchased acrylic to make support for deeper dirt in the back of the tank/moss pit, ideal for molting. Another way I will use acrylic is to build two water sections right into the tank. The water will probably end up being about 5 inches deep. Much better than my current setup.

The next piece to this new setup is an ultrasonic humidifier. Since this is a terrarium with a large mesh top, I’m getting a humidifier to keep everything nice and comfortable for my crabs to breathe. The humidifier and LED lights will both be connected to a smart plug that will have the humidifier on a schedule to activate occasionally. Another advantage to using this smart plug is that I can control it with Alexa.

“Alexa, trigger my crab humidifier.”
“Alexa, turn off the terrarium lights.”



After doing some digging around on the internet I discovered chia seeds can be planted in Crabitats, adding a nice green look to the tank. So naturally I just bought some chia seeds.

Other things I’ve bought include two large fake plants from Exo-Terra and Frog Moss. I’m hoping all this green will make my terrarium not so boring. I’ll also be purchasing eco earth, aquarium sand, and aquarium pebbles. I will probably go into my woods to find interesting rocks and sticks to add to my tank. Washed/Boiled of course.

This is the part where you guys come in. Are there any things I should buy to add to the tank? I’m sure many of you have amazing tanks and I’d like some tips about this.

Anyway, I figured I would round all my thoughts up by writing this, and I hope I get some useful feedback about this setup. Let me know what you guys think! I will keep you all posted as I set this up over the next few days.

Good luck with it! Sounds amazing, even though I personally would of gone for at least a medium.... The small doesn't offer them much walking room - and also moulting space - and the footprint is pretty much equivalent to a 10g.


Oh well, will be following with interest!

Edit: I would reconsider building things out of arcylic are siliconing it to the tank. The bond will quickly fall apart due to the oils in the arcylic and flood the tank. Much better to use a glass bowl and silicone rocks onto it, or just use a tupperware container doubled up IMO.

Also consider moving that deeper sub part more forward, like to the front so you give your guys plenty of substrate space - since you mentioned you have one the size of a tennis ball!

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The Exo-Terra tanks are very expensive. I’m aware things will be tight haha! I’m counting on the vertical space to give them room to walk around. Currently the 10 gallon I have has enough room for my crabs to walk around, but no room for deep substrate or vertical climbing. I really think this will give me the best of both worlds, and the crabs will have plenty of cozy places to hide.


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I am concerned about the tank size with that large of a crab. We don't recommend jumbos in anything under a 48x18 inch tank so they have space to move, and they also need 12 inches of substrate to molt safely. I have an 18x18 base terrarium for my gecko and I personally would not keep crabs in that tank unless it was a few mediums or smaller. There is just not enough space for them to be active enough, claim territory, or molt.

wodesorel wrote:I am concerned about the tank size with that large of a crab. We don't recommend jumbos in anything under a 48x18 inch tank so they have space to move, and they also need 12 inches of substrate to molt safely. I have an 18x18 base terrarium for my gecko and I personally would not keep crabs in that tank unless it was a few mediums or smaller. There is just not enough space for them to be active enough, claim territory, or molt.

I understand your concern. Unfortunately I simply don’t have the funds or space to have a tank that large. I believe the crab will be happy in the new tank, even if things are a little cramped. Keep in mind I’m going from a 10 to a 33 gallon tank here. Stating the crab is the size of a tennis ball might be a slight overstatement, the crab itself is not that size. My crab would be classified as a med-large crab. It’s been hard to convince my family to get larger tanks because they simply don’t understand the extent of the hermit crab hobby. I’ve had this crab for over two years and he is still going strong, very active, and very colorful. I will admit that his current tank he is definitely not very stimulated, and the dirt is way too shallow for him. These are the main issues I’m trying to address at the moment, and getting a tall tank is the best way to do it. Besides, I will have all of the other accommodations like fun climbing items, consistent humidity, premium food, salt and freshwater, and a large place to bathe in water. He also has a very small friend. I wouldn’t let a hermit live alone. Since the tank I got is such a weird shape, it can be hard for people to understand how I will utilize the space. I will try my best to make my crab happy in what I bought.

I hope you will try to understand my situation.

I understand space issues, but for the price of that exoterra you could get a used 55 (heck, probably a 90), heating, sub and decor and still have pocket change left!

PixelPlex22 wrote:

wodesorel wrote:I am concerned about the tank size with that large of a crab. We don't recommend jumbos in anything under a 48x18 inch tank so they have space to move, and they also need 12 inches of substrate to molt safely. I have an 18x18 base terrarium for my gecko and I personally would not keep crabs in that tank unless it was a few mediums or smaller. There is just not enough space for them to be active enough, claim territory, or molt.

I understand your concern. Unfortunately I simply don’t have the funds or space to have a tank that large. I believe the crab will be happy in the new tank, even if things are a little cramped. Keep in mind I’m going from a 10 to a 33 gallon tank here. Stating the crab is the size of a tennis ball might be a slight overstatement, the crab itself is not that size. My crab would be classified as a med-large crab. It’s been hard to convince my family to get larger tanks because they simply don’t understand the extent of the hermit crab hobby. I’ve had this crab for over two years and he is still going strong, very active, and very colorful. I will admit that his current tank he is definitely not very stimulated, and the dirt is way too shallow for him. These are the main issues I’m trying to address at the moment, and getting a tall tank is the best way to do it. Besides, I will have all of the other accommodations like fun climbing items, consistent humidity, premium food, salt and freshwater, and a large place to bathe in water. He also has a very small friend. I wouldn’t let a hermit live alone. Since the tank I got is such a weird shape, it can be hard for people to understand how I will utilize the space. I will try my best to make my crab happy in what I bought.

I hope you will try to understand my situation.

Most of us who have been around the forum for a while are very familiar with the Exoterra enclosures. .

This is why we really advise against them in general.

While they can be modified to accomodate the substrate depth necessary (using aquarium silicone to glue acrylic inserts in behind the doors to maintain an even depth of sand and eco earth across the width of the habitat), they really don't have the overall width necessary to house hermit crabs as large as yours is.

If the shell and crab together are anywhere near tennis ball sized then yes, this setup is too small.

It would be cheaper to get a larger tank from craigslist or a doller per gallon sale.

While crabs may appear to be doing fine for a while, they can also linger with injuries or stressors for some time without us being aware.

Climbing space is important but deep substrate and tank footprint are essential for them to thrive.

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Not to sound like we ganging up on you... but remember floor space (and in particular moulting space) is only the floorprint to the size of of the tank. Additional levels do increase floor space, but does not equate to more usual floorspace - they mostly spend time on the floor, and at most they will have room to run 18 x 18... regardless of levels.


I always consider it as crabs aren't helicopters, they can only utilise the amount of available surface area you have available.

Having had 60cm tall (and prior to that, i beleive I had a 75cm tall tank) the height is great, but they not something like fish that can utilize the increased volume.

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If you go to an family run Fish Store you could find really cheap tank prices as well. Like, I saw a 20L for 6.99 USD (Coincidentally two days after spending 40.00 an my current 20, and that was even Dollar per Gallon)

aussieJJDude wrote:Not to sound like we ganging up on you... but remember floor space (and in particular moulting space) is only the floorprint to the size of of the tank. Additional levels do increase floor space, but does not equate to more usual floorspace - they mostly spend time on the floor, and at most they will have room to run 18 x 18... regardless of levels.


I always consider it as crabs aren't helicopters, they can only utilise the amount of available surface area you have available.

Having had 60cm tall (and prior to that, i beleive I had a 75cm tall tank) the height is great, but they not something like fish that can utilize the increased volume.

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It would be funny if they had propellers on their shells.

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No really, it’s fine. Thank you all for the constructive criticism, I really do appreciate it. I do understand that my crab is a bit large for the enclosure, but I will try my very best to make this work for him. I think I can make a unique crabitat that may not meet all the recommendations of this forum, but will still be a happy home for my crab nonetheless. For example, what I lack in space I make up for in other areas. Hopefully with a little bit of ingenuity I can strike a balance between a fun filled tank, and proper space for my crab. I do have hope that I can make him happy in this enclosure that I purchased. If this tank is really so bad I will not let him suffer in it and I will remove him from it. I do have a backup plan if this tank ABSOLUTELY does not work out for him. Let’s just wait and see how it turns out. Now that I know about size issues, I’d like feedback about different things. Such as suggestions about items to put into the tank, or just helpful tips.

I also wanted to use one of their terrariums for a crabitat. But, substrate wise, the tank is no good. The lip under the door does not reach 6 inches. I was wary of the lip and emailed them to see if any of their terrariums' lips reached a height of 6 inches, they didn't have one that did. You said you hermie has become the size of a tennis ball, meaning he will need DEEP substrate, and Exo Terra isn't going to cut it for long.

Bob'sBucketofRain wrote:I also wanted to use one of their terrariums for a crabitat. But, substrate wise, the tank is no good. The lip under the door does not reach 6 inches. I was wary of the lip and emailed them to see if any of their terrariums' lips reached a height of 6 inches, they didn't have one that did. You said you hermie has become the size of a tennis ball, meaning he will need DEEP substrate, and Exo Terra isn't going to cut it for long.

They can be modified with a piece of plexi in front to hold the substrate in. It's not pretty but it is functional. I would be concerned about the weight of the sand when doing that though, it may end up maxing out what the tank was designed to hold.

wodesorel wrote:

Bob'sBucketofRain wrote:I also wanted to use one of their terrariums for a crabitat. But, substrate wise, the tank is no good. The lip under the door does not reach 6 inches. I was wary of the lip and emailed them to see if any of their terrariums' lips reached a height of 6 inches, they didn't have one that did. You said you hermie has become the size of a tennis ball, meaning he will need DEEP substrate, and Exo Terra isn't going to cut it for long.

They can be modified with a piece of plexi in front to hold the substrate in. It's not pretty but it is functional. I would be concerned about the weight of the sand when doing that though, it may end up maxing out what the tank was designed to hold.

I use eco earth and only a limited amount of sand. I don’t think the tank will be maxed out at all.


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In regards to the dollar-per-gallon sales, I talked to a Petco employee and they should be having that sale either mid-June or mid-July (I can't remember which). Or you could also check the Facebook marketplace. I got my 30gal there for $20!

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