HCA: Hermit Crab Association

There's this weird smell coming from my tank that's smells kind of like fecal matter but not quite. No bistable signs of mold plenty of that though. Problem is it's in their old cage that the climb in and almost never leave. What else could the smell be even after I've clean up the fecal matter to the best of my ability it's still there. Also my crabs limbs are changeing from this nice dark color they had when I got them to this light one is somthing wroung? Thanks for your help. Will post picture

Here's the picture http://i1377.photobucket.com/a...mage_zpsf0ce98a9.jpg

I would take the metal cage out. If your tank humidity is in the correct range, it will likely start to rust. That could be what you are smelling. Make sure your substrate is not over saturated and make sure your temperature and humidity are in the correct range, I read somewhere that if the humidity is out of balance with the heat then mold is more likely.

Search for any food they may have drug out of the food dish and tried to bury. Several times I have found items I thought they ate all of and found that they just tried to bury it making the tank smell. It could also be that there is not enough air circulation in the tank. You want a little but not a whole lot so the humidity stays in.

Over wet substrate will stink to high heaven to! It can also mold underneath. Dig down and check your substrate.

Is that a muffin shell? Horsejazz, please read the following links about choosing a shell. The first is an introduction, the second page is a really special one that helps alot.http://www.hermit-crabs.com/shells.html ... lpics.html