HCA: Hermit Crab Association

My name is Sean. I am currently 20, when I first discovered my affinity for hermit crabs, I was merely 13. Although I research before purchasing, I was, indeed, yet another one of those oblivious hermicrab purchasers. I knew nothing about them and doomed my first two hermitcrabs to a slow and painful death (Thank you petstore, for knowing nothing). I dedicate this, my newest creation, to them.

So, what do you get when you combine an experienced and highly successful reefer (Coral Reefs) with a love for hermit crabs?
…
..
.
This.

Check the photobucket for more!

http://s736.photobucket.com/user/RawrSe ... 20paradise

This is a 90 gallon biotope dedicated to land hermit crabs. It features a fully cycled freshwater aquarium as well as a fully cycled and established saltwater aquarium. Using my expertise in the reef hobby, I have been thus far successful in maintaining the saltwater to be the exact chemistry of natural seawater, down to the exact ppm of nitrate, phosphate, and even iodine in it’s less toxic form, iodide *as all marine inverts require this, I assume so do land inverts!!* Not only that, but the salinity, dKH, and even PH are as equal to natural sea water!

Supported life: (Note: All life is carefully chosen for their ability to survive in both fresh and saltwater. Everything, and I do mean everything listed below, with the exception of fish, of course, do in fact venture into both fresh and saltwater regularly)
30Ish Coenobita clypeatus
2-4 Coenobita compressus
2 Coenobita perlatus (That I’ve had for nearly 4 years!)
2 Golden Claw Fiddler crabs
3 Red Clawed “Tree/Fiddler” Crabs (One has been with me for nearly two years)
2 Asian MudSkippers (Amazing creatures, fish that walk on land!)
1 Saltwater Damselfish
1 Saltwater Zebra Nerite snail
1 Saltwater Redbanded Trochus snail
School of local, wildcaught cardinal fish
2 Freshwater Nerite snails
10Ish misc. wild saltwater hermitcrabs (A few of the exotic ones were purchased from a local fish store and one was even transferred out of my reef tank)
3 saltwater ghost shrimp
1 saltwater sand goby
2 freshwater tiger barbs (haven’t started stocking the freshwater side with cool things yet!)

I will, when I can manage to take a reasonable picture, update the photobucket with pictures of the various fiddler crabs and mudskippers.

Questions, comments, criticism? (Please!)

I...I....*faints*

That tank is incredible! It really looks like it'd be the perfect environment for land hermit crabs.
But.. well, I hate to say this, if you really have almost 40 hermit crabs with only 1/3 the floor space in a 90 gallon, they are severely overcrowded.
When it comes to land hermit crabs, what's really important is the.. well, land! It's important that they have the space to roam and excercise, be able to get away from each other, regulate their body temperatures and moisture levels, and most importantly, molt safely. 40 hermit crabs could not molt in that small land section safely. They don't molt on top of each other, they don't take turns to molt, they will end up piling up at the bottom of the tank and cannibalising each other, fighting, having difficulties molting and attacking each other.
The tank really is great, it's just not a very friendly design for the sheer number of crabs you've put into it. The depth of the substrate matters, but the floor space matters too. They either need a much larger land section, or another large tank to house them all. I'm sorry to have to tell you this when it's obvious you've worked very hard on this tank, but their numbers will dwindle really quickly if left alone like this.

Rocky wrote:That tank is incredible! It really looks like it'd be the perfect environment for land hermit crabs.
But.. well, I hate to say this, if you really have almost 40 hermit crabs with only 1/3 the floor space in a 90 gallon, they are severely overcrowded.
When it comes to land hermit crabs, what's really important is the.. well, land! It's important that they have the space to roam and excercise, be able to get away from each other, regulate their body temperatures and moisture levels, and most importantly, molt safely. 40 hermit crabs could not molt in that small land section safely. They don't molt on top of each other, they don't take turns to molt, they will end up piling up at the bottom of the tank and cannibalising each other, fighting, having difficulties molting and attacking each other.
The tank really is great, it's just not a very friendly design for the sheer number of crabs you've put into it. The depth of the substrate matters, but the floor space matters too. They either need a much larger land section, or another large tank to house them all. I'm sorry to have to tell you this when it's obvious you've worked very hard on this tank, but their numbers will dwindle really quickly if left alone like this.

It's not 1/3rd the space. They have a 2ft L 2ft W 7in Deep land area, and I said ish because I'm really not sure of the numbers.(Do note that these numbers are an overestimate.) I haven't added any in a few years and a lot of them are small. I also have an ISO for any molters that I happen to catch before they dig. Edit to mention that their ISO is their old 55g. Also: Where as I don't rely on this, I have seen some of my hermits stop half-way into the sandbed and molt. I've always kept them on very deep sandbeds. There are plenty of failsafes for this setup, I made sure of it.

Very nice looking set up. I'm not one for mixing a bunch different animals into one tank but it sure is pretty. Love all the wood and the huge pools a very nice. What size are the pools?

CallaLily wrote:Very nice looking set up. I'm not one for mixing a bunch different animals into one tank but it sure is pretty. Love all the wood and the huge pools a very nice. What size are the pools?

Whats your take on the mixing of animals?

As far as the pools go, they hold approximately 5 gallons of water WITH all of the rocks and such included, on each side. Without, it's about 15G. They are 1FTx2FT.

love it thanks for sharing, really enjoyed viewing. happy crabs

It may be a lot of space, but it's simply not enough space for the sheer amount of crabs you've put in there. They won't stay small, or complacent, forever. They're not sweet and cuddly animals, and stressing them out will lead to them lashing out on each other eventually.
I'm not trying to put you down or anything, I'm sure you're a great hermie owner! It's just that I'm worried for their safety. You might not even know anything's wrong until you next do a deep clean and find yourself a few crabs short. Or fights might suddenly break out and you'll find limbs everywhere. It's not a fun experience for the owner and certainly not for the crabs.
If you have a spare 55, that's perfect! You could set that up as a land tank and split them up. Moving them to another tank to molt is unnecessary work for you and unnecessary stress for them at a particularly stressful time. Crabs are fortunate, and unfortunate because they're so hardy. They can be put through a lot and still appear fine, but the problem is people won't notice anything's wrong until it's too late.
I can't force you to do anything, but I'm urging you to make that change for their safety and sanity.

the tank looks great! But I agree with rocky, I will only keep a dozen or so in my my 115 gallon with 4x1.5 feet x 10 inches of substrate. When I've done a deep clean my crabs were molting in 5 inch caves they made for themselves. Imagine 15 crabs trying to do that in your substrate space that's not even 1/3rd the space.

It's a beautiful tank! I'll bet it took a lot of time and effort to get it all set up. I can only dream of having something like that!

RawrSean wrote: Whats your take on the mixing of animals?

As far as the pools go, they hold approximately 5 gallons of water WITH all of the rocks and such included, on each side. Without, it's about 15G. They are 1FTx2FT.

I just feel it's very difficult to provide every species with it's exact needs and space.

Nice! I bet the crabs love having such large pools.

CallaLily wrote:
I just feel it's very difficult to provide every species with it's exact needs and space.

Nice! I bet the crabs love having such large pools.

Oh. I can understand that. The life I've chosen have relatively basic needs. I'm very experienced at keeping them separately. Together is no issue. As far as molting goes, I've been separating them into an ISO for as long as I've had crabs. This may be oldschool thinking but I prefer it because I've found that an increase in humidity really helps them with molting, but is less beneficial to ones that aren't molting. I'm a firm believer that the key to successful molts is water. In an ISO, I can contr it really well. I take this stuff seriously.

Aren't you worried that the mud skippers might be dangerous for your crabs or other tank inhabitants? They are naturally opportunistic predators and they do eat crustaceans as one of their natural food items. I'm sure that a very large crab would be fine but a smaller crab or some of your fish might turn into a target.

Alrighty I'm gonna elaborate here.

I think your set up is beautiful, I really do. HOWEVER, I really don't think you're listening to us. In a nutshell, all I'm seeing are excuses.The fact that you can't give an accurate number of crabs really worries me. I keep as close as an accurate head count as possible on my crabs and I notice when someone doesn't come up. With all yours, that's not really a feasible task. And because I'm not gonna go digging, I'm gonna assume someone killed them. I also have considerably less crabs than you, so your risk is much MUCH higher than mine. Even though you say a lot of them are small (have you measured them btw?), they will grow and that is a problem of its own. Jumbo shells I ordered just came in today and I don't even need them. They're the size of my fist and my hands aren't tiny. What are you gonna do when they're all like that?

While technically yes, the needs of a hermit crab are relatively basic. Food, water, humidity, substrate - we all thought we were giving that when we first started out to some degree whether it be a KK or a decent set up. However, it delves deeper than that. There are tricks to be learned, what can and cannot be done for food and water, that heck, even a substrate difference of a couple inches can be the line between life and death. And yes, while separating them into ISO for molting is possible, we don't recommend it for a very good reason - stress. How would you feel if you were on the brink of one of the most vulnerable times of your life and then some big scary something reached down and dropped you into a foreign place? And for the humidity, an "increase" in humidity does nothing for molting and everything for breathing. They don't have lungs, as I'm sure you know and I'm sure with the pools that you have no problems with having the humidity at the minimum 80%. And they're underground, how do you know an increase helps them? And how is it less beneficial to the non-molters? Breathing easily is pretty beneficial in and of itself, I find.

And the key to successful LIFE is water. The key to my successful molts is leaving them alone and not overcrowding them.

fraksocks wrote:Aren't you worried that the mud skippers might be dangerous for your crabs or other tank inhabitants? They are naturally opportunistic predators and they do eat crustaceans as one of their natural food items. I'm sure that a very large crab would be fine but a smaller crab or some of your fish might turn into a target.

No because these particular mudskippers don't get bigger than a few inches. There isn't anything in the tank that they couldn't even try to eat. Also, I keep them well fed.

Yuka wrote:Alrighty I'm gonna elaborate here.

I think your set up is beautiful, I really do. HOWEVER, I really don't think you're listening to us. In a nutshell, all I'm seeing are excuses.The fact that you can't give an accurate number of crabs really worries me. I keep as close as an accurate head count as possible on my crabs and I notice when someone doesn't come up. With all yours, that's not really a feasible task. And because I'm not gonna go digging, I'm gonna assume someone killed them. I also have considerably less crabs than you, so your risk is much MUCH higher than mine. Even though you say a lot of them are small (have you measured them btw?), they will grow and that is a problem of its own. Jumbo shells I ordered just came in today and I don't even need them. They're the size of my fist and my hands aren't tiny. What are you gonna do when they're all like that?

While technically yes, the needs of a hermit crab are relatively basic. Food, water, humidity, substrate - we all thought we were giving that when we first started out to some degree whether it be a KK or a decent set up. However, it delves deeper than that. There are tricks to be learned, what can and cannot be done for food and water, that heck, even a substrate difference of a couple inches can be the line between life and death. And yes, while separating them into ISO for molting is possible, we don't recommend it for a very good reason - stress. How would you feel if you were on the brink of one of the most vulnerable times of your life and then some big scary something reached down and dropped you into a foreign place? And for the humidity, an "increase" in humidity does nothing for molting and everything for breathing. They don't have lungs, as I'm sure you know and I'm sure with the pools that you have no problems with having the humidity at the minimum 80%. And they're underground, how do you know an increase helps them? And how is it less beneficial to the non-molters? Breathing easily is pretty beneficial in and of itself, I find.

And the key to successful LIFE is water. The key to my successful molts is leaving them alone and not overcrowding them.

You speak as if I'm not having successful molts.
I'll gladly admit that I didn't think it was as big of a problem as you're clearly explaining and that I will setup another system for them. I already have a 225g planned for them in the coming years. Most of the crabs in here were serious rescues. They wouldn't be alive right now.


First on the easy part -- the increase in humidity helps with the substrate in the ISO. An where as a humidity of 90% detrimental to hermit crabs that haven't dug, it's really helpful to the ones that have. I watch my crabs very carefully. I examine regularly and when I see a molting sac form or notice irregular behaviors, I move them and watch.

Secondly, I don't have a head count because I haven't added or taken any in ages. There isn't a time where they are all above ground, and I don't have the memory capacity to remember each of them. All I go by is my 6 month substrate replacement. I haven't found dead crabs in quite a few replacements. As for their size, I never planned for this to be their permanent home. Again, I never said this was their final home, I already have my 225 in the planning stages.

How does all of that sound?