Buried for 3 Months (Death Smell & Sand Movement)

[myruggy89]

Some Context:

I currently have two medium PP in a 10 gal tank. I have had them for over a year and they have successfully molted earlier this year. At the time I had three hermies, and they all molted around the same time in hermit crab sand that I had purchased online. I didn't have enough sand as it was only about two inches deep at the time, so I added coconut husk (they love that!) and they molted in the sand and husk. That lasted about two months. I have since cleaned the tank and revamped it with new sand (beach) and it is now at least 4-5 inches deep and they all went crazy and buried themselves. One aggressive crab came back up and decided to dig out another crab already in his molting process and stole his shell. The molting crab died not too long after that (in isolation). The aggressive crab stayed above the sand doing his happy crab things. The other living crab decided to come back up within a few weeks of burrowing and was super active for about a week. He then buried himself and I have not seen him since. It's been about three months. I found him during one of my tank cleaning sessions, so now I know where he is. But I have not seen any sand movement.

My Questions:

1) Can there be periods (Weeks) of no sand movement from a molting crab? (There was allot of sand movement with their last molting period).

2) Will I be able to smell the death smell through the sand, or do I need to move it and expose the crab?

3) Can they molt with the sand compacted around them? (They made caves during their last molt, but this time they did not)

4) Can temperature cause a crab to take longer to molt?

[LadyJinglyJones]

Hi-Hi!

Good job getting the sand fixed up! You can actually add a little more sand/coco fiber, as 6" is a good depth to be starting with.

If a crab is taking shells from its buds, you may need
A) more shells
Or
B) the right size/type of shells

How many shells do you have per crab & do you know what kind they are?

Also, are you offering calcium and protein daily? What does a weekly diet look like for your little guys? Agression can be caused by competition for resourses. Calcium, protein & shell shortages can all be common culprits in crab-on-crab crime.

As for your questions:

... Definately you can go a long time without surface signs of digging (if your sand is deep enough). Months is not uncommon. (During this time they should not be dug up if at all possible. Surprising a crab mid-moult while it is vulnerable can lead to its demise. )

The fact that you say they didn't build caves makes me think they either weren't moulting (just digging around underground and back filling their tunnels, as they often will) or (possibly) the sand isn't moist enough and can't hold a tunnel properly (?). I say this because if your sand is sand castle consistency, the tunnels will be created as they dig - it's neat to watch a crab dig along the side of a tank, they push and pack sand with their legs, creating a little 'window' against the glass as they go. The sand around them isn't loose, generally. Is that what you found when you exposed your crab, or was it sitting in loose sand? They can not moult without a cave.

To test sandcastle consistentcy, squeeze some sand... if it holds its shape & isn't wet, it's okay. You can test deeper down by putting a pencil, chopstick, or straw down into to sub, and if the hole holds all the way down, you're crabs should be able to tunnel.

As for temperature affecting moults, they theoretically won't begin a moult in an inappropriate temperature because temp (along with dark, how much reserve energy they've stored, and other factors) is one of the things that helps to control the release of moulting hormone. (Moulting hormones control moults, of course.)

That said, things can go wrong physiologically with any animal (humans and crabs alike!) and their bodies can do things that aren't ideal for their own health. Keeping the temperature within a safe range is a very good idea. 80° f is a good minimum air temp for them. Under the sand will typically be closer to room temp.

What are yout temp and humidity?

Finally, you might not smell death from underground. Not knowing is the curse of the crabber. It's something all experienced crabbers can relate to, but you do gradually learn to live with the wait. :roll:

[Lewisthecrab]

One of my crabs(Amber) was buried like that and she sadly died while she was down under and I did not know she died but one day Lewis dug her up and she was dee-diddly-dead. So I guess it depends on the size of the crab and type of substrate. If it's a jumbo then no worries. But if it's a teenie, then you got probs. Also some coco fiber beddings can block the smell so I really don't know. You can try smoothing down the sand around it and if it smells BAD, then she has died. I hope your crab lives!

[myruggy89]

Wow! Thank you for the quick and detailed response. You posed many good questions. It seems that my current main issue to tackle is the humidity in the tank, and to be more prudent about offering calcium and protein regularly. I added natural peanut butter to the tank last night and my hermit crab went crazy for it!

My sand is sand castle consistency, but my buried crab isn't in a cave. I found him one evening while cleaning the tank and fluffing the sand in areas. When he went under, he went down in the corner of the tank. I found him in the center, just there. How long should I give him before I assume the worse? His last molt was around two months long, but there was quite a bit of sand activity where he was.

Also, I have extra sand and coconut husk that I would like to add to the tank now to make it deeper. Can I do that now with a buried crab, or should I wait until he resurfaces or I discover that he is dead?

If he is dead, will the sand near him smell bad, too? Or will I need to expose him completely before being able to get a whiff of the stinky smell.

My first crab that died never gave off a foul odor, but mold ended up growing all over his naked body.

[LadyJinglyJones]

Yeah, sometimes a deceased crab won't smell. And I imagine the sand around a dead crab would only smell if conditions were right for the crab to become (apologies for this visual) a bit gooey and seeping into the sand.

A note on protein: animal protein is important. Shellfish, insects, crustaceans, fish, poultry, egg, and such are key to contented, healthy crabs. They aren't about the vegetarian life.

Your non-moving crab:
Was it maybe a surface moult? It sounds like he wasn't exactly under the sand.... (?)

It isn't surprising you found him in diferent place from where he went down: they travel horizontally as well as vertically.

Crabs can spend a surprising length of time not moving post moult. It can take a long time for them to get to a point where their bodies are fully muscularily/metabolicaly/behaviourally function-y again.

This is why we shouldn't dispose of crabs that seem 'dead' just because they apear immobile. No one wants to throw out a crab only to find out it just needed another week of chill-time.

However, if your crab is dead, at some point it will manifest signs of this. Smell, fungus, gradually falling to prices.

While waiting on your uncovered crab, it should be isolated. You can use the cut off top of a pop bottle (no lid & cleaned) to isolate him in-tank - push the edge into the sand a little and the other crabs won't be able to get in. Try to perhaps make it dark - as it would be underground were that where your crab had molted.

Also, because humidity is a concern, I'd recommend adding damp moss (or clean cloth wetted, or sponge) under the pop bottle with him to help increase humidity. Offer marine salt water and fresh water in bottle caps (or other small dish close to him.)

Post-moult crabs will need to.eat their exo to regain calcium. If he has done this offer more calcium, protein... a healthy variety diet. I like to offer cod liver oil & egg if I know a crab is recently up from a moult.

The crab can dig himself out when he's ready.

You can add sub wherever your uncovered crab isn't (so around the pop bottle) by adding an inch every 24 hrs. -just don't pack it down, and it won't affect crabs underground.