HCA: Hermit Crab Association

I'm not sure if its just me being paranoid... but I think my crabs get smaller when they molt. :/

I just got 3 new crabs about a month ago and I dug up 2 which were molting. I've been checking on them periodically and they don't seem much bigger. :/

I keep the tat at a good Humidity, (I don't have a Gage, but its a 10 gallon tank and the glass is usually steamy and the sand is at sand castle consistency) and the temperature seems to always stay around 70 degrees. They're all PPs, I give them Distilled Water, (no salt water yet; working on it) and they usually have a variety of food choices, even though I've only seen them eat one or two times. I also haven't gotten any Cuttlebone for them yet.

What am I doing wrong?

Doesn't sound like you're doing anything wrong. I don't know why they would shrink. I've never heard of that before. Sometimes they molt and you can hardly tell a difference in their size, mine have done that to me before. BTW, cuttle bone is not absolutely necessary. I rarely ever see mine eat. You really need salt water, but that won't make them shrink.

Timmy1992 wrote:(no salt water yet; working on it)

I think this may be the answer.

You will need saltwater, or more specifically, land hermit crabs need saltwater in order to expand their shells during molting (unlike other arthropods such as insects and tarantulas which have managed to utilize just their own body fluids in conjunction with air).

Use the saltwater recommended for use for marine/seawater aquariums - any of the current brands may be useful.

Zoo med/glub hermit crab salt water conditioners are not recommended, as is table salt used for food.

^^ Ditto what Mudcrabdude said.

For now, just keep it very dark and quiet in the tat and do your best to not check on them. Let them do their thing and they should be fine. You DO need to pick up some marine aquarium grade salt water asap, though. Good luck with your guys!

I've read that sometimes the crabs will look smaller after molting due to the absence of water during the molting process while they are under for a long period of time. It should self-correct as soon as they are finished with the process and have access to fresh and salt water again.