Crabbytalk.com - Hermit Crab Care, food/diet, crabitats, & pictures of land hermit crabs

Molting is a natural process for hermit crabs. In order for a hermit crab to grow it must molt. Molting may occur once a year for larger hermit crabs or once every few months for smaller (tiny crabs).

To know if your hermit crab is preparing to molt look for these signs:

1. The hermit crab will probably become lethargic (it won’t move much).
2. Your hermit crab will start digging.
3. The hermit crab’s coloring may become ashy, the coloring probably won’t be as vibrant.
4. Your hermit crab will probably eat a lot of food and drink a lot of water.
5. The hermit crab may develop some eye crust or the hermit crab’s eyes may look cloudy. This will go away after a molt.
6. Your hermit crab will develop a molt sac. This molt sac holds water and helps to break the exoskeleton when the hermit crab actually molts. The molt sac doesn’t store food.
7. If your hermit crab is missing a limb it will probably develop a gel limb. Once your hermit crab molts the missing limb will be regenerated, but it may be smaller than the original.

If you notice these signs you may want to isolate your hermit crab in what we call an isolation tank. This is usually a smaller tank with lots of moist sand or eco earth, some water (both saltwater and dechlorinated water), food, and a hiding place. Make sure that the humidity is 78-80% and the temperature is around 78-80 also. Some of us, myself included, allow their hermit crabs to molt in the main tank without problems. This is really a personal choice. If you don’t have a good isolation tank with gauges and proper conditions then you should probably leave them in the main tank to molt. Moving them into a plastic box without good heat and humidity really isn’t good.

The hermit crab molting process may take several weeks to several months. Your hermit crab should dig under the substrate when it’s actually going to molt; if it doesn’t you may be using the wrong kind of substrate. When a hermit crab molts above ground it is called surface molting. Gravel, rocks, wood chips, and pebbles are not good molting substrates. It is better to use sand, forest bedding or eco earth as a substrate in your tank. Sometimes a hermit crab will surface molt even with the right tank conditions. If a hermit crab surface molts in your main tank I would recommend isolating the hermit crab in its own tank immediately. Move the exoskeleton with the hermit crab into isolation. When a hermit crab molts on the surface other hermit crabs may attack it. Since the hermit crab is very soft immediately after the molt it will not be able to protect itself from other hermit crabs.

Once your hermit crab has dug under the sand avoid the urge to dig it up to check on it. Leave your hermit crab alone to molt. Keep the tank warm, humid, and dark. Your hermit crab knows how to molt, there is nothing you can do to help. Your hermit crab may be under the substrate preparing to molt, molting, and recuperating post-molt for up to eight weeks. I know, that’s a long time to leave them alone. Larger crabs will typically take longer to molt than smaller hermit crabs. When your hermit crab resurfaces it will be very hairy, have very sharp nails, and if it was being provided a good diet its coloring will probably be very vibrant. Here is a really good picture of a hermit crab’s sharp nails after a molt.

When your hermit crab molts it sheds its exoskeleton like a snake. It then eats its exoskeleton post molt to help it recover. Don’t freak out if you find hermit crab limbs in your tank, it’s probably hollow exoskeleton that your hermit crab didn’t eat. Leftover exoskeleton that your freshly molted hermit crab didn’t eat can be given to your other crabs, it’s good for them! It’s also a good idea to keep other calcium sources in your tank for fresh molters; cuttlebone, crushed oyster shell, and eggshells are good sources of calcium for your hermit crabs.

It will usually take your hermit crab several days to a couple of weeks to fully harden and be active again. If you isolated your hermit crab, you don’t want to put it back into the main tank until it is eating regular food and climbing around the isolation tank like it wants to escape. You will probably find that your hermit crab is very shy post molt and seems like it is afraid of its own shadow, this is normal and it takes about a month for the hermit crab’s normal personality to return.

Just a warning. Many new crab owners think that their hermit crab is dead when it has actually molted. If you come across a crab that looks like it has fallen out of its shell check the shell carefully to see if in fact there is a smaller crab tucked in the shell. When a hermit crab has molted the soft abdomen will not fall out of the shell, only the hard exoskeleton will shed.

Visit Stacy’s photo gallery for pictures of freshly molted hermit crabs and exoskeletons.

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This is Houdini, one of my Cavipe hermit crabs, on September 12, 2005. I have had him since January 14, 2005 and he hadn’t molted. He had been rather lethargic and his coloring was very ashy. Last night I was checking out the 55 gallon crabitat and I saw Houdini and he had molted! You can see in the above picture that he didn’t fit in his shell, but now he is considerably smaller.

You can see in the above photo that he now easily fits into his shell, it’s amazing how much he shrunk. You can also see that his coloring is much more vibrant and he has very sharp nails.

It looks like he lost his left walking leg during molt, but other than that he seems to be fine. He was out playing with the ruggies last night.

Yesterday I wrote about the fact that hermit crabs do not regenerate their eyes and eye crust. One of my purple pinchers had a bad molt back in May and came up with what appears to be some kind of growth around his eyes and discoloration. Initially, I blamed this on poor diet and ethoxyquin. This same PP just molted; in the picture above you can see that his coloring is better, but the eye growth remains.

While we do not know the long term effects of ethoxyquin or other chemicals in commercial hermit crab food, I don’t know that I can continue to blame those chemicals on the bad molts. This crab has had an all natural diet since April, it’s so hard to say what the long term effects could be from just a small dose of some of these preservative. It’s also hard to say what really causes these deformities in our hermit crabs, it could be diet, environmental conditions (crabitat), or just genetics. I struggle with the issue of the hermit crab diet. While I continue to feed all natural foods to my hermies, I have to wonder just what these chemicals really do to our crabs. There are so many crabbers who have used foods from FMR for years with no ill effects.

Julia Crab, of the Epicurean Hermit, is now making life a little easier for those of us who want to feed a natural diet to our crabs. She now packages her Hermit Crab Cuisine which is all natural with no preservatives added a quite a reasonable price. You can learn more about the Hermit Crab Cuisine on her site at http://www.epicureanhermit.com/. I have purchased two packages of her cuisine which I sprinkle on fresh foods several times per week.