My Hermie's shell has changed shape & cracked

[Guest]

1. What kind of substrate is used in your tank and how deep is it?
2-3 Inches deep and 1/3 tank is sand other is Eco Earth mixed with a small amount of sand

2. Do you have gauges in the tank to measure temperature and humidity? If so, where are they located and what temperature and humidity do they usually read?
Yes we have gauges. they are both located near the top of the tank. the temp guage reads typically between 70-75 F and the humidity we keep between 75-80%

3. Is a heat source used in the tank? If so, what?
yes we have an under tank heater.

4. What types of water are available (fresh or salt) and how is the water treated (what brands of dechlorinator or salt mix and what ratio is used to mix it)?
We have both salt and fresh water. we use Instant Ocean salt for the salt water and Instant Ocean water conditioner for the fresh water.

5. What kinds of food do you feed and how often is it replaced?
We use Zoo Med hermit crab pellets

6. How long have you had the crab and what species is it, if known?
The crab we are having an issue with is DB, a purple pincher whom we have had since Sept 6th, 2014

7. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
All 3 are small hermit crabs so we have them in a 10 gallon tank with a screen top. in order to keep the humidity in until we can get a better top we have wrapped about 2/3 of he screen in saran wrap. the hermits can not reach this in any way.

8. How many crabs are in the tank and about how large are they?
We bought 3 Hermit crabs on Sept 6th, 2014. We bought 1 purple pincher (named DB) and 1 Ecuadorian (named Tank) from Petco and 1 Purple Pincher (named Boulder) from PetSmart. We are currently having an issue with DB.

9. How many extra shells are usually kept in the tank, if any?
Currently there are 4 extra shells in the tank varying in shapes but the sizes are all comparable to the crabs. a couple a bit bigger and a couple the same size as them.

10. Have there been any fumes or chemicals near the crabitat recently?
no

11. How often do you clean the tank and how?
we spot clean the tank as needed, which is usually every few days. the water dishes and sponges get cleaned every few days. we have yet to clean the substrate as it is still in great shape. no smells or slimes or bad colors anywhere.

12. Are sponges used in the water dish? If so, how are they cleaned?
yes we have a sponge for each dish which we clean with hot hot water every few days then rinse with the dechlorinated fresh water.

13. Has anything new been added to your crabitat recently?
no

14. Is there any other information you would like to share that might be helpful (anything that is regularly part of your crab care, playtime, bathing, etc.)?
when we got the hermits on Sept 6th, we bathed them all in salt water bath before introducing them to the tank. Both Boulder (came from a different store) and Tank (who came from the same store as DB) have been active and handled the entire month. we spritz the tank daily with the dechlorinated water to keep the humidity up. Tank has now been buried for a few days, with zero night activity. He recently stocked up on water so we are assuming he might be molting so buried he remains.

15. Please describe the emergency situation in detail.
DB has been buried in the Eco Earth Substrate since Sept 7th. He buried himself without stocking up on the water. I know this as I checked on them numerous times in the middle of the night to make sure the humidity and temp were holding correctly. we figured he was just acclimating himself to his new home so left him be. he went in with a long tubular shell and we peeked on him today because we were unsure as to whether he was living or not. He is alive, however his shell has changed shape and cracked. it has shortened and gotten fatter. IT WAS NOT CRACKED BEFORE, we checked each crab carefully prior to purchasing them to make sure they were active and in good condition. (as good as a pet store can get). we are worried the crack in the shell may be harmful to him and wondering what would cause his shell to change shape and crack.

[CallaLily]

Hello. When you say his shell has cracked, are you talking about the shell he is wearing or his exo? Also, did he resurface or did you dig him up? Digging is not recommended and usually causes more harm then good. It's best to leave a dug down crab to do his thing.

I'm confused by this statement:

Tank has been buried for a few days, with zero night activity. He recently stocked up on water so we are assuming he might be molting so buried he remains.

Did this crab dig down or did you bury him?

A few other concerns. Your substrate should be 3x as deep as your largest crab is tall but no less than 6 inches. This is to ensure tunnels/caves are stable and to lessen the chance of crabs running into other molting crabs underground. Temp range for PPs is 75-85F but Es need 80-90F. With both species housed together you should aim for around 80-85F. Humidity is ok though many crabbers recommend keeping it up around 80%. Double check ingredients on the commercial food. Many brands have unsafe ingredients and most crabbers chose to skip over feeding them entirely. A variety of fresh foods offered regularly is best, even if you continue to offer a safe commercial food too. You'll also want to offer some more extra shells. 3 extra shells per crab is the minimum recommended. Too few shells can lead to shell fights. Personally, I don't recommend handling new crabs at all until they've successfully molted with you at least once.

[Guest]

Yes we dug him up just to check if he was living... We gently moved the dirt from a top him because another site said if no activity for a month after getting a new crab to take a peek just to make sure its alive.. Dont handle it.. Just peek., which we did and noticed right away his shell has actually changed shape ( gotten fatter and shorter) and cracked. No its not a different shell either.

As far as my comment about our second buried crab Tank...i was just staying we were not going to dig him up or mess with him at all because he was showing signs of a molt as opposed to DB

[Guest]

Oh and Tank buried himself. And i was talking about DBs actual shell.. Not exoskeleton. And how can i raise the temp in the tank with the undertank heater?? Will more substrate help with raising the temp??

[Ellysara]

I'm not familiar with any way a shell could have changed shape, but as far as the crack goes, there is nothing you can do about it until he comes up on his own, really. Unfortunately, that other site gave you incorrect information about going digging for a crab. Even if he did not stock up on water, your crab could still be molting, which can take between 1 and 3 months, and some crabs take even longer!! It is never recommended to go digging for a crab unless it has been at least that long. Disturbing a molting crab can cause stress, injuries or death. When he comes up, he will probably change shells as long as you have other appropriate ones available. But if the crack doesn't bother him, then that is fine too.

As for your heater question, where is it mounted? Although the name is Under Tank Heater, they should actually be mounted on the side of the tank, above the substrate level. This is because the substrate will block all the heat from getting to the top and your goal is to heat the air. Putting a heater on the bottom will also dry the substrate out and could be a fire hazard. Adding more substrate will not make the temp go up, but it will make your crabs happy to have more room for molting.

[Guest]

Ok thanks.. And we did place the heater on the side of the tank not the bottom.

[CallaLily]

quote="et_turtle"]
As far as my comment about our second buried crab Tank...i was just staying we were not going to dig him up or mess with him at all because he was showing signs of a molt as opposed to DB[/quote]

I see now. I was reading it wrong. Sorry about that.

Ellysara gave good advice so I won't add to it. Let us know if you have any more questions.

[wodesorel]

I'm rather stumped about how the shell could have changed shape. Cracking can definitely happen, usually from a fall - but natural shells are never malleable. If the shell was previous cracked it could have widened over time as the crab shifted around inside,and that could make it appear wider where the crab is located. Do you know what kind of shell it is? There are plastic shells out there - those would melt and deform if exposed to high heat.

[Guest]

I am not sure the exact name of the type of shell he has. Its a long tubular one. If he fell and cracked his shell it had to have been done before we got him as he buried himself the very next day after we got him and has stayed buried since. I had never heard of a natural shell changing shape either, thats why we are stumped.