HCA: Hermit Crab Association

Yesterday I noticed a black spot at the bottom of the tank and knew it was a dead crab. I dug down today and it was indeed a dead one. I got all the black sand out and a bunch of the surrounding sand (I kept smelling it to see if it didn't smell like death). I got as much as I could but then the sides of the hole started collapsing. I accidentally dug up a freshly molted little crab - he's super pink and still had his exo near him. He seems ok - I put him in a little terra cotta pot that lays sideways with some dirt. I just checked him and he was moving out of that to go somewhere else.

Questions:
1. I got as much of the horrid smelling sand out from around where the crabbie died. Is this all I need to do or do I need to completely change all the sand? It's a 55g tank.

2. The sand at the bottom is REALLY wet and I don't know why. Does this possibly mean I don't have enough air flow in the tank or something else? I have the aquarium hoods that the tank came with along with a towel (from the winter to help buffer them from the outside wall they're against) over the top. Heat is a few UTHs on the back of the tank and a heat lamp at one end.

3. Do I need to do anything else with the little molter or just let him figure it out himself?

Thanks for any advice!

Can't quite give advice, but I do know how it feels to lose a crabby, so I am sorry for your loss. I dug up a crab that I didn't realize was trying to molt THREE times. For two days he was above ground im ISO with his EXO and then dug down, so your little guy who is molting should be fine. Oh crabbies are tough.

I've lost crabs who buried, and when I eventually found them there was little left and no black sand around them - I would worry about a bacterial bloom if it's nasty smelling black sand, especially if the bottom is really wet. If you got rid of all that and the rest of the sand smells okay, I think you SHOULD be fine.

Is there standing water in the sand at the bottom, or is it just really wet? Do you use a humidifer or run bubblers? Is there a chance either of your water bowls are leaking? If you don't have other crabs down, I would thoroughly mix up the sand to redistribute the super wet stuff. You could also build a false bottom, so if you end up with excess water it can drain under that and not endanger your crabs.

As far as the molter you dug up, I'd isolate him so no other crabs can get to him - until he's hardened up and finished eating his exo and eating/drinking normally, he should be kept separate. A tupperwarer container within the main tank works great for that so his conditions are correct. Just handle him as little as possible, let him do his thing, and there's no reason for him not to be fine.

Parts of the bottom sand were soupy and parts were sand castle consistency. I don't have a humidifier or bubblers, but I do wonder now that you say it, if the water bowl is leaking. I noticed last week that the fresh water was really low really fast, but chalked it up to evaporation.

I am sure I have crabs down, but with such a large population (over 20), I think I pretty much always have crabs down. I do need to add sand, since I took so much out today, but I'm not sure of the safest way to do that. Any suggestions?

My other issue is I added a cleaning crew of isopods not long ago and I don't want to put sand over them and lose them (will I?).

This tank is not as easy to get straight as my 29g tank was. Ever since we moved to Houston, it seems like we've had bug issues, crabs dying, etc. I bought the tank in November and we've had a huge population of springtails in it...to the point where they were crawling all over the crabs and making them twitch. (and it was driving me nuts) I took off the top 2 inches of sand, cleaned and baked everything and added the isopods. Things seemed normal, but I've noticed them coming back again. They must be in the sand I got here, because I've never had them before. I'm afraid to get more sand for fear of introducing even more bugs.

Definitely check that dish for leakage - Even with heat bulbs running, my water doesn't evaporate much if it all.

Springtails aren't bad to have, but I hate bugs so they would bother me too! As far as adding sand, with your isopods if you just gently add the sand (pre-moistened) a handful at a time and don't pack it, they should be able to unbury themselves if you aren't adding more than a couple inches.

I understand the pain of having crabs down constantly - I have 17 in my 55 so there are always a bunch down. Obviously digging is bad and needs to be avoided if at all possible so I'm not going to recommend it. The excess water is a concern, and personally when my tank had a similar situation I did go digging so I could re-mix everything and avoid bacterial bloom. I would take an inventory and see exactly how many crabs are up, and decide from there if it's worth the risk. IF you decide digging is necessary, you'll need iso's set up for any molters you may discover. Also, if you go that route, you'll probably lose most/all of your isopods.

If you find out what the cause of the extra water is (like the water dish) and solve it, the water will probably eventually dry up on its own or at least not get worse. You can check other areas of your tank for bad smells by taking a straw and poking it throughout several spots and checking/sniffing the sand it picks up. If everything seems okay, I don't see the harm in waiting, and maybe with luck you'll wind up with most/all crabs up at some point and re-mix the sand then.

In my first 2 tanks, I had the same problem. It was from misting, and I didn't think I was misting THAT much. But in an effort to keep the humidity up, I flooded the tank. Now both of my current tanks have false bottoms, and I will never build a tank without one. I also learned to keep several containers of moss to humidity. I rarely have to mist now.
And no matter how hard I tried to get rid of the bacterial bloom, it just never totally went away. I can't recommend that you dig, but if you can catch them at a time when most are up (happen in my 55 about once every few months), maybe you can get it straightened out.