This will be discussed on the website, so I want some ideas from you. Shell disease are fungi that feed on a hermit crab's chitin. They appear as a black spot on the hermit crab's exoskeleton (or skin). Does anyone know a cure for shell disease or how hermit crabs catch it? Lobsters and similar crustaceans are also known to be susceptible to shell disease.
I saw one poor little hermit crab in a pet shop who had a terribly deformed leg and was missing all his leg tips on each leg. He had at least six shell disease spots, four on his legs and two on his back . Poor guy...
It's more commonly called 'Shell Rot'. It is contagious. Beware!
I have a crab who had a hole in his exo from the 'rot'. As it is contagious, I am under the impression that it is passed from crab to crab and seacreature to seacreature. Luckily, when a crab molts, generally the shell rot is removed and the exo is allowed to begin reparations.
Sometimes, however, the shell rot gets too bad before the crab can molt and it is consumed by the bacteria. Sad, but true.
How do you stop it? Well, honestly, I'm not entirely positive.
Some suggestions on possibilities, however:
Wash your crab often. That should remove some of the bacteria and allow it to stay low. Bacteria grow very well in moist conditions. Keep your crabitat less humid for a while until your crab can overcome the shell rot.
A probably very effective way to treat: Use fish antibiotics. These are drops (generally) that are put in the water the fish swim in. This is most often used for fin or scale rot, very similar to shell rot. By being exposed to this antibiotic, the bacteria dies. You would, of course, have to use a bath to administer this method.
The pre-molt sac will be far back on the crab. Shell rot generally starts on their legs and will begin to make a HOLE in their exo. That's how you can tell the difference.
Can they have shell rot while they are molting??? Mine just molted and when I checked on him a few days after I noticed the exo fall off he was covered in fuzz and the abdomin was black and he stunk really bad. I've accepted that he died in molting, but I'm wondering if it was this. I thought it was mold, but was it bacteria??
Shell rot grows on the crab's exo, and I don't think it does on the actual crab's body. Your crab was probably dead a long time before you found him, and had begun decomposing.