Dull shells

[kgbenson]

Out of idle curiosity I buried some polished shells in 100% coco-fiber to see what would happen in terms of the finish. As some may recall there has been off and on descriptions of what may or may not be part of shells losing their luster. Coco-fiber is slightly acidic, and acid will etch shells. For those of the seeing is believing POV, try putting a shell in vinegar.

Well, the shells buried in moist coir certainly dulled faster than the shells on the crabs in 5:1 sand:coir. Shells in just sand were completely unfazed. Granted the shells in the sand alone were not being moved about so as to abrade their surface. I had them buried for about 6 weeks or so.

Now I will also mention that I have mixed a small amount of crushed oyster shell in with my substrate, and this may temper the pH a bit. If you don't I cannot speak to what will happen.

Will this slight acidity affect the crabs themselves? I don't know, but it sure does take the shine off a shell. And I would remind people that one does not need to be dissolved to have ones physiology disrupted over time and that a hermit crabs shell has a significant component of Calcium. If one were to submit a crustacean for necropsy, the 2006 Manual of Diagnostic Tests for Aquatic Animals calls for Davidson's AFA Fixative which is a mixture of Formalin, Alcohol and Acetic Acid (found in vinegar) because this will "reduce autolytic changes in tropical crustaceans and the acidic content decalcifies the cuticle.

I know crabs can molt in 100% Coir, the question is not can they, but can they do so consistently and under most peoples tank conditions. Or is there a substrate or mix of substrates that gives them a statistically significant higher chance of a healthy molt for the typical crabber. Without doing a whacking huge study over a long period of time I can't answer that from personal experience . . . but there does seem to be a few things that are less than ideal about 100% Coir.

In other words, just because something works for one person, or a few people, in their limited experience, does not mean that the same technique will work for everyone, or even anyone else.

Keith

[SebbyCrab]

Not that I had my guys in 100% coir, because I had 3 deaths due to tunnel collapse on pure EE. But 4 weeks buried in pure coir, when I was using it, had the same effect on a polished tapestry turbo from HCP.

I can post before and after pics if anyone would like.

[scyllarus]

hmm. i kind of wonder why a 5:1 mixture works so well, then. i've been using straight sand, and while i've only kept my crabs for four months or so, i've had two successful molts (there's one that's still down, and that's worrying me).

perhaps the slight acidity helps with the molters that have trouble getting their exo off? i mean, my crabs seem to wait underground for some time before actually performing the molt, and while i assume that's because they need to stimulate molt hormone, i'm wondering if being underground so long in a 5:1 mix may soften the exo just enough to help get the old exo off while not enough to produce fatal effects?

also, what about half-and-half tanks? why would the crabs dig into a substrate that is potentially fatal to them? i suppose there's not straight EE in the wild, though, so there's not a chance for natural selection to favor crabs that don't molt in acidic substrate?

perhaps the people with straight EE have crabs who really love to eat calcium treats?

[CallaLily]

Thanks for the info Keith!

hmm. i kind of wonder why a 5:1 mixture works so well, then. i've been using straight sand

I think the key is there's just enough EE to help with humidity and stronger tunnels but not enough to effect the pH too much. I have a mix of sand/EE (about 5 -50 lb bags sand & 2 bricks EE) at the moment but I plan to switch back to straight sand next deep clean. Well there will still be a small amount of EE because I leave some old substrate behind. I've had many successful molts in both straight sand and a mix. I've never used 100% coconut fiber -though I have at one time had a thin layer of coconut fiber on top of sand that the crabs eventually mixed in. But now I'm rambling. I'm good for that.

[kgbenson]

hmm. i kind of wonder why a 5:1 mixture works so well, then. i've been using straight sand, and while i've only kept my crabs for four months or so, i've had two successful molts (there's one that's still down, and that's worrying me).

Most soils, even most beach sand have some organic component. IN this case the coir serves that function. It is also pretty innocuous stuff compared to other available media. The pH change is mush smaller than say sphagnum peat (not the moss, the peat)

perhaps the slight acidity helps with the molters that have trouble getting their exo off?

I don't know, but I would not make that leap, unless you were willing to test it, and that can take time and statistics.

i mean, my crabs seem to wait underground for some time before actually performing the molt, and while i assume that's because they need to stimulate molt hormone, i'm wondering if being underground so long in a 5:1 mix may soften the exo just enough to help get the old exo off while not enough to produce fatal effects?

Hmmmm, I doubt it. At least I don't think it would be something you could get the balance on to be able to count on it. Also, most of the calcium that it removed from the old shell is for the animal to re-use and losing it to the environment is not something you want to have happen.

Here are a couple of other caveats. Many people will mix oyster shell into their substrate. This sill buffer some of the acid. Also, some sands can have a higher pH depending on the product - and this can be hit or miss. The only real way to know what the pH of you substrate is is to test it. I know of no data however that would tell you what pH to shoot for in terms of an ideal, or even a good range.

also, what about half-and-half tanks? why would the crabs dig into a substrate that is potentially fatal to them? i suppose there's not straight EE in the wild, though, so there's not a chance for natural selection to favor crabs that don't molt in acidic substrate?

They may. Though I don't think it is as black and white as that. After all, some folks have had animals do well on all coir. What we are discussing here is population based judgment. Some animals will tolerate things that others cannot. What the average person wants to know is, what is the system of management and set of equipment that will keep my crabs alive the longest and with minimal disease and death. There will always be animals that tolerate something that the general population cannot, or situations where less than idea materials function well enough.

perhaps the people with straight EE have crabs who really love to eat calcium treats?

I don't know - but it is an interesting question. Perhaps they use their salt water pools more to replace other ions. Interesting questions. What I think would be interesting is to put three groups of crabs on three different substrates but otherwise treated essentially the same. Sand (one would have to be picked, I would opt for play-sand from say, HD just to make it as "real-Life" as possible), Strait coir and a 5:1 mix. Define the characteristics of each substrate at the beginning, middle and end of a "test period" and then monitor the groups for a variety of things. Molting, molt success, changes to color and other exoskeletal appearances, chances in hemolymph bloods gasses and salt balance, use of pools etc. And then compare the groups and see if anything is significant.

Anyone got the room, the time and the cash?

Keith

[Kilimanjaro]

I know I've been using 100% EE for a while and my shells do get dull. This is why I have decided to switch over to a mixture. It seems better this way, and while I have had numerous great molts on EE, I have had fatal ones, too, and I think it would be better not to risk it.

Thanks for the experiment info!

[suebee]

I think if given a choice of a 1/2 coir and 1/2 sand tank you will find that the crabs chose the coir side. I believe this to be due to the more humidity and temperature difference. Crabs look for warm moist places to be. As coir breaks down it gives off heat. I found in testing of containers of substrate that the coir container would hold up to 6 degrees of heat more then sand alone. I also found more coir in the tank to dull the shells but it also seemed that after being in 5:1 ratio that the crabs exo seem to be more shiny. Maybe the sand polishes the exo more but I tend to think its the acid in the coir that dulls the exo. I would think that on a molting crab where the new exo is thinner and less hard that could be a problem. I do not have any prof of that its just what i believe from what i see in my tanks. I also worry about the possibility of splinters in the coir. I know that the liquid that the crabs secret and put on their feet to push out the sand that helps the sand stick in a tunnel and burrow seems to dry quicker and not stick as well on the sand. I would think that could cause burrows or tunnels to collapse.
I do like to have some coir in the substrate because i have watched molters when they give me a molters window munch on coir and on crushed oyster shell pieces. It also seemed to help my substrate have more humidity without it being to moist on the very bottom..

[tlivs]

I also worry about the possibility of splinters in the coir.

im just wondering why you would put crushed oyster shells in your tank then if you have this concern? ive been thinking about this or a while now, and in the wild no substrate is ever going to be without debris such as pieces of wood, leaves, etc. Crushed oyster shells i have noticed are around the size of small-tiny pebbles that could potentially get stuck in the shells of the hermit crabs. Im not saying it would even happen, but it is a possibility

the random sticks and leaves and rocks that are found in coir would be equally found in the wild in their natural substrate so i dont see how this would be a problem
and sue you now that i have absolutely no intention of being rude, but i am truly curious what you think

ps. sorry this is a bit off topic

[suebee]

I find the oyster shell to be rounded and not sharp. What i buy is more of a powder. I do check the coir when i put it by running my hands through it. I have found sharp sticks and try to remove any i find. I did have a crab a that got a stick of coir stuck in his tail and he left his shell for the salt water dish to try and get it out. I found this out when i lost him and checking him under the microscope found the splinter in the tail. I havent had any problems with oyster shell and i know that so many shell pieces are on the beach in the sand. A good part of beach sand when you look at it under a microscope is shell pieces. The shell pieces even make the beaches in Bermuda look like pink sand. When the coir gets mixed in with the sand the sand does tend to break it up even more. If i bought oyster shell that didnt seem to be a powdered i would put it in a morter and crush it a bit more before adding it to the tank. The crabs seem to really enjoy the oyster shell and i think its a big benefit for the underground molters to be able to eat some when calcium is needed.
I have heard people say that they had a crab get a piece of oyster shell that cut the crab but i havent had that. I think its due to making sure the oyster shell is finely ground.
Im sure things can still happen with any substrate, a piece of coco nut shell could end up buried or even a piece of food that became hard. I just try to take what precautions i can.

[suebee]

I wonder if you had any left over BPs from molters you could put in the EE as a test to see what happened to them. Maybe do a stress test or take photos before and after. Measurements of the exo thickness before and after? I know vinegar breaks it down. Vinegar broke down baked chicken bone and egg shell too. It made the vinegar higher in calcium we use it to make a healthy salad dressing.

[Kilimanjaro]

I found a way to refinish the shells which have dulled!

If you take a small amount of extra virgin olive oil and massage it onto the shell it regains its original look. I rub the EVOO onto the shell first, let it sit for 10 minutes to absorb, and then dry off the excess with a paper towel.

So far, my shells seem pretty refurbished.

[kgbenson]

So far, my shells seem pretty refurbished.

Neat - how long does this last?

Keith

[suebee]

its great if there is a way to refurbish the shells but i would think over time the shells must be getting thinner. weak shells worry me due to the inside possibly collapsing and causing the tail of the crabs to get cut. Keith do you think the shells inside showed any difference? I think the inside of the shells seem more porous and there fore might be effected sooner then the outside.

[Kilimanjaro]

I've noticed it lasts for a few weeks or so, and then the shell goes back to dullness :/

[suebee]

I would like to tell you about a adoption i just did. I adopted 3 crabs that have been kept in total EE for 5 years. My first thought was, ok, the EE didnt kill them.. I was given them and a box full of shells that they had grown out of or new ones for them to grow in to. The crabs are very nice and friendly. All are large crabs.. Now looking at them I was shocked at what the EE has done to them. Not only were all the extra shells given to me dull to a point that even the ones that you could tell were at one time polished they all felt pitty and none were shiny. Most of the shells seemed to be stained brown too. Looking at the exo of the crabs who have successfully (?) molted in the EE substrate for 5 years they all seem pitty and dull. When i look at my current crabs that are the same size of these crabs I only see shiny exo with no pits. Every one of the crabs has at least one leg that is not in the proper condition. legs going in the wrong direction. All the legs are there but it looks like as they molted they were not supported properly or maybe the EE started to biodegrade the exos? I knew that that others i personally know did research and found that EE was not good as a substrate on its own but seeing this first hand was shocking. It does prove that the crabs can and will live in EE, however They do not look as healthy as any of my crabs of the same size who have been in a substrate with mostly sand. Maybe the sand acts as a polish but i tend to think the EE has eaten away at not only the shells but the Exo..
Now i feel that this is not just my opinion because i feel comfortable that i have seen the facts.. I already trusted Hermit crab patch and ELHC and im very glad I did. I will continue to use the 5 parts sand to one part EE and never more EE then that. I have also been putting Worm castings in my substrate. I just dump the extra from the day before bowl into the substrate. This was suggested to me and oked by ELHC and its been working out well.
I wanted to point this out to hopefully help others decide on what substrate they should use. I should also mention that the crabs given to me were Coenobita clypeatus and Coenobita brevimanus I will let you know how the molts go but i think it will be a while due to all of them having nice new pin shoes.. They may chose to molt due to the new substrate ill let you know if that happens.. Blessings, sue