The moon and molting (straws)

[Richard]

Greetings !

this is my first time posting here. I would like to commend you guys for keeping such a well organized and active forum. Keep up the good work!

I am in the process of setting up an environment for hermit crabs. I am going to get Straws and Indos. The setup I am working on will be around 110g. One part beach, one part jungle. I want to try and make their environment as close to nature as possible. I have been reading everything I could online, a couple of novice books and The Biology of Land Crabs. Biology of Land Crabs, left me with a couple of questions that I hope you can help me with. I don't know if I should have made 2 posts with one question in each. I hope it is ok that I post both of my questions in this thread.

My first question is related to the tide, and moon phase. From reading Biology of Land crabs I got the impression that the tide is very important to a lot of land (and aquatic) crabs. So my question is, if you have noticed a difference in the level of activity, and/or behavior in you're crabs during the various phases of the moon ?

Next question is about straws molting. In Biology of land crabs, it says that some crabs (not hermit crabs but a different kind of exotic land crab) will dig down 5 feet (1.5 meters) in order to molt. I am wondering how deep the straws would go, if you gave them "unlimited" substrate ? And since they live near the beach, I also wonder if they dig down so far, that they hit the water or a particular level of moisture ? As far as I understood, from what I have read about Straws online. The molt is often where it goes wrong for this specie.

They need to maintain a very high level of salinity to live, even higher than the levels found in the sea water, where they live. While they are not molting, this causes them no problem because they can constantly regulate the water in their shell. But during a molt, they do not have this option. In a typical tank setup. The straw will dig down to molt, and have no salt water available while dug down (maybe some salt, if you mixed the substrate with salt water). The bigger they get, the longer the molts takes, and so the longer they are deprived of salt water. I am speculating that maybe the lack of salt water during molts is a part of the reason why they tend to die prematurely in captivity. Do you think this theory sounds sane, or am i missing the point ?

[aussieJJDude]

Hello!
Quick question, where are you sourcing these crabs from? In US and canada, its particularly hard to source straws, let alone indos.
Have you also kept crabs before? Not to rain on your parade, exotics - particularly straws - are known to be difficult to keep, and not forgiving like other species like PPs. I would encourage keeping PPs until you get some time under your belt, abd have greater success in crab keeping.

First thing first, lunar phases. Even though i have not had straws or Indos lunar phases do not impact on crabby behaviour.

High levels of salt in the substrate can cause salt burn, a thing that effects us probably more than the crabs - but still damaging to their bodies IMO.

A good spacious tank is a good idea regardless.

In captivity, we are unable to provide many things that the wild has to offer. I have kept crabs just shy of a foot of substrate, and they still dig with to the bottom with ease. I imagine that in the wild they would dig a couple of feet with ease.

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[Richard]

I am from Europe. Straws and Indo's are the only kind of land hermit crabs available to me. I do know that Straws are hard to keep. But I will be ready for them. I set up a small computer to control humidity, temperature and lighting. I follow the caresheets available on this site, both the one that apply to all species and the ones for Straws and Indos.

I read somewhere that it's a good idea to mix the substrate with salt water to prevent mold. But if it causes the crabs to get burns, then I guess that is not such a great idea.

i imagine the beach part of my crabbitat to look something like this



This would be 1/3 of the beach environment.The remaining 2/3 will be stacked on top of the tank in the picture. And yes, I am indeed horrible at drawing

My idea with this tank is that the Straws can dig down until they reach the level of moisture they need while molting. I do have some concerns that they might dig down into the water and drown. But at the same time, if they go 2-5 feet deep on the beach, they will most likely hit the water there as well.

[soilentgringa]

I am from Europe. Straws and Indo's are the only kind of land hermit crabs available to me. I do know that Straws are hard to keep. But I will be ready for them. I set up a small computer to control humidity, temperature and lighting. I follow the caresheets available on this site, both the one that apply to all species and the ones for Straws and Indos.

I read somewhere that it's a good idea to mix the substrate with salt water to prevent mold. But if it causes the crabs to get burns, then I guess that is not such a great idea.

i imagine the beach part of my crabbitat to look something like this



This would be 1/3 of the beach environment.The remaining 2/3 will be stacked on top of the tank in the picture. And yes, I am indeed horrible at drawing

My idea with this tank is that the Straws can dig down until they reach the level of moisture they need while molting. I do have some concerns that they might dig down into the water and drown. But at the same time, if they go 2-5 feet deep on the beach, they will most likely hit the water there as well.

Unfortunately you can't set a crab tank up like this because the soggy sand will form a bacterial bloom, and crabs will dig down and die in flooded substrate.

Providing an even amount of sandcastle consistency substrate and pools large enough for the crabs to submerge in will allow them the ability to dig and molt safely, and have room for swimming.

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[aussieJJDude]

My bad. A little bit of salt is fine, however if there is too much it can cause salt burn.
Like SG said, that setup will not work in something as small as a 110g... maybe something that extremely larger - even then, bacteria blooms everywhere - it will erode as well.


I would still personally suggest keeping just indos, experience is both through knowledge and hands on learning IMO. Maybe in a couple of years then add a couple of straws once your familar with crab care - and had gpod success with Indos.

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[wodesorel]

2 to 6 years is all you will get with Straws, and no, we still have no clue as to why. For a time double strength salt water was all the rage with straws (have no idea where that started) but it does nothing for their survival.

The only thing that has been noted time and time again is using correct UVB specialty lighting. They are not the easiest to set up for hermits and they need changed every 6 to 12 months and it isn't the cheapest bulb. Being in Europe you should be able to find Arcadia bulbs easily, and these are being regarded as the best these days. That along with a varied seems to extend their lives to 4 to 6 years.

We are definitely missing something. Keep in mind as well that molting for any crab is the hardest part of their lives, and each subsequent molt is that much harder on their bodies than the last. Since they regenerate and never really grow old, that is how natural deaths occur, at some point the molt takes more energy than they have to give. When it comes to premature death in straws, I am not so convinced that something is going wrong with the actual molt, rather it is simply that they run out of the energy (or something else) that needed to complete it.

Any chance you can read German? There is a great German language hermit crab forum that has a lot of research on exotics!

[Richard]

I am glad that I pitched the idea here so I got the understanding of why, it is a bad idea to set up a tank, like the one in the picture. I could add an extra tank on top and fill it with sand also. That way there would be a total of 35 inches of substrate. I have not read anything about bacteria growth in salt water tanks, so honestly I know nothing about it. Soilentgringa wrote that the soggy sand will create a bacterial bloom. So either way it would be a terrible idea to make a tank as in the picture. But how about making the top layer of the sand, sandcastle consistency and the bottom of the sand tank, a bit more wet ? I dunno if this would also attract a bacteria bloom ?

I assume the crabs needs to keep their salinity level even while molting. With no salt water present in the substrate where they (Straws) molt, it seems pretty logical that they have a hard time. Especially as they grow older and the molt takes longer.

About this whole salt thing. I went online to try and figure out what levels of salt is present in the sand near the beaches where the Straws live. To my surprise it is typically very high. This is because during high tide, sometimes huge waves will hit the beach (but not often). We are talking about "monster waves", not just big ones. The wave wets all the sand. The sun dries the sand, and what is left from the wave, is salt. Repeat this over a long period of time and you got very salty sand. Many of the islands they inhabit are also affected by monsoon rain. This will probably wash away the salt, one time a year. But not all of the places they live are affected by monsoon rain.

About the double strength salt water that Wodesorel mentioned. I think it is natural to assume that, it might help the crabs if you give them water with a salinity that is close to, the level they carry around.You try and think of things and reasons why they die prematurely in captivity. But to test something out, you need +6 years, so it's not easy. We also don't know why Straws need such an high level of salt. But if it did not help them in some way in the wild, they would not function in that way. I am not German, I do understand a little bit, unfortunate not enough to take part in a forum

I already got the UVB bulbs, and fixtures. I got the kind that is intended for rain forest. I could not find any recommendations about bulb type in the caresheets (or maybe i missed it). So I guessed that they probably need the rain forest kind.

AsssieJJdude I understand that you might be afraid that I will not be able to care properly for the Straws. I agree with you, that you also learn from hands-on experiences . But it is still very limited how many times you need to interact directly with the crabs.

A crab get's hurt (attacked or otherwise)
a crab got stuck on something
you see a crab sticking it's claw into another crabs shell
a crab dies
a crab is being denied access to food or water.

All of the things above require "hands-on" but they are the same for all land hermit crabs. And if I got in a situation I did not know what to do about. I would probably take a picture and ask about it in the "emergency section"

I think the big issues, with keeping straws, for a lot of novices like myself. Would be keeping the humidity and temperature high enough, and getting substrate that is deep enough. But as I mentioned earlier I got a computer to take care of the temperature and humidity for me. And I think I might go for the 35 inches of sand substrate. Then there is food, and water. The foods recommended are very well described in the care sheet section and replacing the water is trivial. I do understand that the norm is that people keep their crabs under less than ideal conditions.I don't mean users on this site, but the majority of kids that get them because they are an "easy pets". I watched a lot of youtube videos about hermit crabs, and I estimate that 95% of the tanks in these videos have serious flaws in their setups. A lot of them even have titles like "how to set up your hermit crab tank" and "how to care for your hermit crab". Occasionally there is someone with a beautiful setup, and that is really inspiring. But mostly the youtube videos makes me a little bit sad to watch.Both for the kid and the crab(s). I am curious as to what experience I need to have in order to keep Straws ? the only difference as far as i see is that they need higher humidity and temperature, and deeper substrate. But maybe there is something else, i am missing ?

[wodesorel]

It's experience with the tank that is recommended, as keeping it at stable temps and humidity, and keeping the sand at the right consistency, and a bunch of other little things (leaking water bowls, addition of too much moisture to up humidity levels leading to floods, etc) is a trial and error process, especially during changing seasons. A year of caring for the tank gives a much more stable base for more sensitive species like straws. PPs can take mistakes in humidity and temp in stride, where the same would likely kill a straw. That is why at least a year is recommended before going with exotics. If you are trying to set up something automatic then it should be tested for an extended period. All tanks start off good, it's the figuring out how they change over time that is the tricky part.

Hermits do not molt on beaches. They go back into the tree line and forest where there is protection from the elements and roots to hold up caves. There will not be nearly as much salt in these locations. Rain also washes away high salt concentrations, which is something we cannot safely recreate. And we are talking tropical rainforest, so monsoon or not they see a lot of rain throughout the year. Too much salt (double the amount found in sea water or more) in substrate with a molting crab causes spotting of the exoskeleton, short term this is not an issue but long term I feel it is a stressor that can potentially turn deadly. I was careless once while mixing substrate and every single one of my hermits can up from molting with these tiny dark spots covering them. I realized it was from the salt when I gave myself rather severe chemical burns changing the substrate out bare handed. Removing some of the heavily effected sand and mixing in non-salted fresh to thin it out completely resolved the issue the next time they molted.

Bacterial blooms are caused by anaerobic bacteria. Technically they do not require standing water or even too much moisture, which is why I have concerns about the amount of substrate you are indicating you want. All this type of bacteria need is lack of light, lack of oxygen, and some moisture. They occur most often with floods and supersaturation as the water packs the sand down tight prohibiting air flow. Sand itself will be enough to do this on its own if deep enough. Blooms are silent killers, they form in the middle of the substrate mass so they cannot be seen, they are deep enough away from light and air that they cannot be smelled unless directly exposed, and because they pump out both methane gas and acid, they can easily kill molters, and what is even worse is the crabs don't seem to know to stay away or if they are molting they cannot move away. I have always felt strongly about bacterial blooms as my first deaths were due to this, in a molting isolation tank that seemed normal and healthy until my hermits did not come back up. Having a giant mass of substrate is its own learning curve, as natural aeration will not occur and moistness will sink towards the bottom. Even with drainage there is a high probability of bacterial blooms unless a way is found to manage it properly.

[mom23]

I’ve had most of my straws (indos too) for a little over 4 years. My substrate is all sandcastle consistency and 12 inches in depth although in hindsight I do wish I had made it much deeper. I keep large water bowls, both salt and fresh because they do like to submerge. I change the water every other day. Both the heat and humidity are above 80 at all times and I do provide UV light along with the regular day and night bulbs I use. I have a large tank (150 gallon) that is full of things for them to climb. They are very active and enjoy destroying everything. They have a diet of protein, nuts, seeds, calcium, fruit and veggies everyday and love fresh food. They love bark and leaves as well. I keep a lot of shells because you know they’re all going to want the same one if I don’t. My tank also has purple pinchers, ruggies, violas, and one lone blueberry. Luckily after this many years they all live harmoniously and honestly the tank at this point runs itself. Having said that it was A LOT of trial and error in the beginning and I have found my large tanks do way better at keeping the atmosphere than the small tanks. I agree with Wodesorel (and this is from my own learning curve that everyone here helped me through) that the initial tank set up is easy compared to the time it takes to tweak everything and get it running properly. I ran my tank for weeks before even getting a crab and then for months after I feel I was always tweaking something. I started off way to big for my own good. I guess my suggestion would be to start off with a few crabs and run your tank first with no crabs to work out some of the kinks. Good luck. My straws are everyone’s favorite. They’re so active during the day compared to some of my others and of course they’re beautiful.


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[mjjluver]

That's a nice looking tank!

[Richard]

It's experience with the tank that is recommended, as keeping it at stable temps and humidity, and keeping the sand at the right consistency, and a bunch of other little things (leaking water bowls, addition of too much moisture to up humidity levels leading to floods, etc) is a trial and error process, especially during changing seasons. A year of caring for the tank gives a much more stable base for more sensitive species like straws. PPs can take mistakes in humidity and temp in stride, where the same would likely kill a straw. That is why at least a year is recommended before going with exotics. If you are trying to set up something automatic then it should be tested for an extended period. All tanks start off good, it's the figuring out how they change over time that is the tricky part.

That's kinda the point of having a computer run the tank. When humidity drops below a certain value in a area, it will activate the fogger in the appropriate part of the tank to raise it. When the temperature falls, it will activate the appropriate UTH and/or the heat lamp. Obviously I am going to run the system for a month before introducing the crabs into the tank. Right now it's winter so it's the perfect time to "stress test" the setup

Too much salt (double the amount found in sea water or more) in substrate with a molting crab causes spotting of the exoskeleton, short term this is not an issue but long term I feel it is a stressor that can potentially turn deadly. I was careless once while mixing substrate and every single one of my hermits can up from molting with these tiny dark spots covering them. I realized it was from the salt when I gave myself rather severe chemical burns changing the substrate out bare handed. Removing some of the heavily effected sand and mixing in non-salted fresh to thin it out completely resolved the issue the next time they molted.

That sounds horrible ! Were the crabs that got burned Straws ? All other species are more adapted to life on land and do not need the high levels of salt, Straws do. You must have extreamly sensitive skin to suffer chemical burns from salt levels twice that found in the sea. Straws carry in their shell, water that is just about twice as salty as the kind found in the sea(depending on what sea). So if they were to suffer burns from water with that salinity, they would get burned from carrying the watermix of their choosing. I am pretty sure we can agree that the Straws don't burn themselves with the water they carry around. And since they do not get burned by that water, why would they get burned by salt concentrations in the sand, similar to the kind they carry around ?

Bacterial blooms are caused by anaerobic bacteria. Technically they do not require standing water or even too much moisture, which is why I have concerns about the amount of substrate you are indicating you want. All this type of bacteria need is lack of light, lack of oxygen, and some moisture. They occur most often with floods and supersaturation as the water packs the sand down tight prohibiting air flow. Sand itself will be enough to do this on its own if deep enough. Blooms are silent killers, they form in the middle of the substrate mass so they cannot be seen, they are deep enough away from light and air that they cannot be smelled unless directly exposed, and because they pump out both methane gas and acid, they can easily kill molters, and what is even worse is the crabs don't seem to know to stay away or if they are molting they cannot move away. I have always felt strongly about bacterial blooms as my first deaths were due to this, in a molting isolation tank that seemed normal and healthy until my hermits did not come back up. Having a giant mass of substrate is its own learning curve, as natural aeration will not occur and moistness will sink towards the bottom. Even with drainage there is a high probability of bacterial blooms unless a way is found to manage it properly.

This is interesting. I think I am going to get a hold of a couple of books about Anaerobic bacteria. The fact that they release methane gas is nice though. Because that means I can add a couple of methane sensors to the tank and keep an eye of the levels. Also if the bacteria don't like oxygen, maybe 5-6 blobbers on the very bottom of the tank would help ? How big a risk is there that these bacteria will infest my tank ?

My substrate is all sandcastle consistency and 12 inches in depth although in hindsight I do wish I had made it much deeper.

But if you had made the substrate much deeper you would have gotten that bacteria bloom, that seems to be a problem ? btw your tank looks amazing !

[ErikRasmussen]

I am avidly following this thread and am excited to see where it goes.

Bacterial blooms are caused by anaerobic bacteria. Technically they do not require standing water or even too much moisture, which is why I have concerns about the amount of substrate you are indicating you want. All this type of bacteria need is lack of light, lack of oxygen, and some moisture. They occur most often with floods and supersaturation as the water packs the sand down tight prohibiting air flow. Sand itself will be enough to do this on its own if deep enough. Blooms are silent killers, they form in the middle of the substrate mass so they cannot be seen, they are deep enough away from light and air that they cannot be smelled unless directly exposed, and because they pump out both methane gas and acid, they can easily kill molters, and what is even worse is the crabs don't seem to know to stay away or if they are molting they cannot move away. I have always felt strongly about bacterial blooms as my first deaths were due to this, in a molting isolation tank that seemed normal and healthy until my hermits did not come back up. Having a giant mass of substrate is its own learning curve, as natural aeration will not occur and moistness will sink towards the bottom. Even with drainage there is a high probability of bacterial blooms unless a way is found to manage it properly.

This bit is news to me because i haven't heard of this before. It seems as though the proposed substrate depth isn't anything more than what Kips tank build or other large tank builds have but a false bottom wouldn't aerate that enough?