My hermit crab is out of its shell, but I saw legs moving. Is it molting?

Hermit crabs will usually bury themselves in the sand when they are molting, but some may stay on the surface. He shouldn't smell like fish, so it is possible he passed. Gently lift him up, or scoop away a bit of sand if he is buried, and observe him for any movement. You should see some movement. If the odor intensifies over the next day or so and he doesn't move, he likely passed.

You can gently scrub the shell with a soft bristled toothbrush. If the brown coloring is due to algae growth, this may help. A minor crack should heal on ownit's own. Maintain pristine water quality to aid in recovery. You can use a home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Perform partial water changes as needed to stabilize chemistry and/or to improve water quality. A vacation feeder block can be placed in the tank to provide extra calcium for shell health.

Crab shells are a concern for causing damage or an obstruction in the stomach and intestines, but usually pass through without incident depending on the size. Normal GI transit time is 3-5 days for such things. During this time you would just be waiting to see if she has any signs of an obstruction. Signs of an obstructions are vomiting, not defecating, acting very painful/depressed and a decrease in appetite. If you notice these signs, then Harley should go to the vet immediately, because she may need emergency surgery. I hope that helps and all is well with Harley.

It is likely he was stressed. Give him some time to settle down and he should be fine. Keep an eye on his feet and toes. If there is any discoloration, have him examined by your veterinarian or a vet experienced in treating reptiles.

Check the water chemistry. Invertebrates can be more sensitive to ammonia levels than other fish. It is always recommended to quarantine new additions in a separate tank to rule out or treat infection or parasites prior to adding to the main tank. Make sure he isn't being harrassed by other fish. As he matures, he will grow and become a potential threat to bottom dwelling tankmates.

First of all if he is in the house, then he is most likely dead as it is too warm to go into hibernation. If he is outside it's not easy to tell, at least not in the beginning, eventually you will know as you will see him start to decompose after a few days of being dead, it will start smelling as well.

Without a physical exam, it is difficult to determine if it is dead or alive. Low temps may cause extreme lethargy in reptiles. Try warming it up slowly, using warm water and a heat lamp, to see if it starts to move. If it was submerged, it may have drowned. To be sure, you can take it to the local veterinary clinic to confirm death.