On molting

Please note this article is old and some of the information may be outdated.

Originally written by Jad Johnson 2003

Perhaps the most traumatic event in the life of your crab, not to mention the trauma for the owner, is a molt. Often for me it begins by checking on my guys in the morning (I find that they like to do it during the night). A momentary flood of panic washes over me when I see crab bits strewn around the Crabarium. “Oh, no. Has he been mutilated, or is he ill?” Then as I realize I have a molter on my hands, I REALLY begin to panic!

Molting (or moulting to our Aussie buddies) is the natural process by which your crab grows. Like all arthropods, they have a hard exoskeleton, or outer shell which does not grow. So about once a year, depending on the size, age, and eating habits of the crab, they will shed their “exo” to complete the growth process. They will also take this opportunity to re-grow any limbs lost or damaged after the previous molt. “But Jad,” you ask, “is there anything I can do to help my little guy out?” I’m glad you asked.

There are some tried and true methods, and then there are more experimental ones. In this article, I’ll deal with standard methods, and will leave cutting edge advances to another day. I will also focus on the above substrate molt. Probably about 95% of my guys molt on the surface. Let’s examine the molting process in segments:

The Pre Molt

If you’re going to help your crab prepare for a molt, you’ll need to know what to look for, right? There are several telltale signs. Some of the more common are: cloudy eyes (like cataracts); slow and lethargic movement; hanging out on the sponge, in the waterdish, or other damp locale; digging in a wetting the sand, and the appearance of gel limbs, if the crab has any missing claws or legs.

Gel limbs are proto-limbs, buds that are the beginning of appendages that were lost previously. They appear well before a molt, but get larger and often darken as the molt nears.
Many land hermit crab owners like to isolate their crabs at these first warning signs. I usually don’t, because when I do, my crabs stay in a little one-gallon critter keeper for three weeks without molting. Of course, when I replace them back in the tank they molt immediately. Usually, I wait until the deed is done before transferring them to an iso tank. My iso tank is about a half-gallon, and I keep it inside my main tank. It is easier to control the humidity and temperature levels this way.

During this pre-molt time, there are a few things you can do to help: Pre-molt baths in water treated with Stress Coat by Aquarium Pharmaceuticals is helpful and practiced by most crabbers. Some more advanced methods include giving your crab honey or Gatorade to give them that little sugar rush to help them increase energy. Some advocate applying natural aloe to parts of their exo. This helps soften the exo.

During the Molt

Not a whole lot to do here. just sit and watch. It is important not to disturb them during the actual even. If possible keep the environment warm, humid, and dark.

Post Molt

Congratulations! The molt is over.. You’re about halfway there. This is often the hardest period for them to get through. If you had just spent several hours sloughing your skin, I bet you’d be exhausted, too! Unfortunately, everything might seem to go right, but the crab still may not make it through this critical time. To help increase your crab’s chances of success, consider these tips:

  • At this point, the crab should definitely be isolated. His soft pink exo is vulnerable to nefarious crustaceans. If you haven’t already done so, GENTLY transfer him to a spare tank, or an iso unit. Some people will take a section of a 2-liter soda bottle with the top and bottom removed to instantly section the crab off with out moving him.
  • Like any other traumatic medical procedure, what the patient needs most is peace and quiet. Try not to handle the crab at this point unless it is absolutely necessary! Too much activity at this point can result in limb damage or loss, and stress to the crab.
  • Be sure to keep the crab’s old exo to munch on. This helps replenish the calcium lost in the molt. I will usually save the uneaten portions of the exo for later molters. If the exo has already been ravaged by Crabarium-mates, then cuttlebone or sterilized eggshells will do.
  • If the iso unit the crab is in is dry, you may want to mist your lil’ guy, because humidity is also important at this time. Remember not to overdo it; a gentle spritz is all it takes. A nearby damp sponge will also help.

After about a week or so, the patient will be ready to rejoin society. Most of the exo will have been consumed; generally the tough leg tips and large feeder claw will be all that remains. At this time your hermit might want to slip into something more comfortable- a bigger shell. Be sure there are several to choose from. Of course, he may like the one he’s already in, thank you very much. They’re so picky about their shells, aren’t they?
For them, it’s exhausting, and for us it’s nerve-wracking. Either way, it ain’t fun. However, your crab’s molt need not be a death sentence. With a little preparation and TLC, both you and your crab will get through it fine. It just takes a little practice and a lot of patience. Pretty soon, you will both be old hats at it. You’ll be calm and reserved. until the next molt begins, then it’s panic city all over again. Oh, Well.

Copyright 2003 Jad Johnson. All Rights Reserved

More articles on molting:
What is molting
Is my hermit crab dead or molting?
Regulation of Crustacean Molting: A Multi-Hormonal System
All about molting by Lisa Loeske
CrabLoverDon on molting