A hermit crab without shell is vulnerable to outside elements and will likely die if not molted or moved into a new home. This is why it’s important to give your hermit crab multiple housing options.
Besides using natural shells, many owners like to use PVC pipes. These are light, clean, and affordable.
Hermit crabs are marine animals and can only survive in the salt water ocean. In captivity they live in large enclosures filled with substrate for digging and hiding spots, fresh water for drinking and bathing every couple weeks as well as supplemental calcium supplements. They need to be in a warm, humid environment and should be misted with dechlorinated sea water (not table salt) during the day to keep them moist. When a hermit crab is missing its shell it is usually molting.
This is a normal part of the hermit crab’s life cycle and it is important for their health to go through this process. Before a crab sheds its old exoskeleton it is in the proecdysis stage which lasts about a day or two. During this time any lost appendages regenerate as limb buds that will unfold when the crab sheds its shell. The crab is also storing up food and water reserves during this phase.
Once the bud of the new limb is ready to emerge the crab will molt. During this process the crab will be a bit smaller than it was before it shed because its body is resizing for its new shell. It will also spend more time in the salt water than usual to help harden the new exoskeleton.
One of the most interesting parts of moulting is when the hermit crabs will line up in front of each other and exchange shells. This happens quickly and is quite a sight to see.
After a hermit crab has molted it will display a great deal of energy and eagerness in its behavior as it searches for a suitable shell to move into. It is best to give a hermit crab multiple housing options at this point and let it choose the one it prefers. Ensure that any shell you provide is at least 1/4 inch wider than the current shell and cleaned and disinfected before placing it in your crab’s cage. It may take up to a week for the hermit crab to move into its new shell.
Despite not having shells, hermit crabs are detritovores and have evolved to rely on shelter for protection. Since hermit crabs have many predators (including birds) and competition for a safe home from other crabs, shell selection is a crucial aspect of hermit crab behavior.
A hermit crab will choose a new shell for a variety of reasons. It may be a result of molting or it could be because it has grown too large for its previous shell. Hermit crabs also switch shells if they are contaminated by sand, mites, fungus or foreign objects lodged in them. It is important to keep a few different sized shells in your hermit crab’s cage and provide him with options. Providing hermies with a range of shapes and colors will help him find the right one for him.
In addition to the size of a shell, color is also an important factor in the hermit crab’s decision-making process. Research has shown that hermit crabs prefer shells that match the background in color and texture. This camouflage provides an effective means of defense.
Hermit crabs also choose the shape of their shells based on a number of other attributes such as space, weight and smell. They may select shells that are asymmetrically coiled to fit the soft abdomen inside. The shells also need to be light enough for hermit crabs to move in and out of them with ease.
A hermit crab’s shell selection is also influenced by other factors such as environmental and social pressures. For example, research on the marine hermit crab Calcinus verrilli shows that the crabs in smaller than optimal shells experience reduced growth rate than those in larger shells. This may be due to inefficient anaerobic respiration in the small shells, which reduces energy available for other activities (Rodrigues et al. 2000).
Hermit crabs are sensitive creatures, and they can be very stressed when they are not in a suitable shell. This is why it is important to provide them with many options in terms of shape and size. You can also clean the shells regularly with a povidone-iodine solution or boil them to ensure that they are free from bacteria and other parasites.
When a hermit crab leaves its shell, it means that it has found another one which it feels is more appropriate for it. It is possible that it has located a shell occupied by a non-kin hermit crab, in which case it may try to evict the other hermit from its new home by fighting it. However, it is not always successful as hermit crabs have been observed forming temporary coalitions to evict their non-kin from their shells (reference).
If the hermit crab is in a molting stage and has left its old shell, then it must find a new one immediately. Otherwise, it will die of dehydration and exposure to the elements. A hermit crab without a shell will be unable to eat or drink, so it is extremely vulnerable.
If your hermit crab has left its shell for long periods, then it is a good idea to separate it into a isolation tank with a fresh, clean substrate and a couple of its most recent shells. The isolation tank should be big enough to let the crab fully bury itself, which will decrease its stress levels and help it to return to its shell sooner. It is also important to make sure that the isolation tank has a good temperature and humidity level, which should not vary too much.
If your crab has left its shell, it could be suffering from a disease. Hermit crabs are at risk of many different illnesses and diseases when they have no protection from their chitinous-calcium carbonate compound exoskeleton. A hermit crab without its shell is vulnerable to everything around it — including bacteria. Its soft inner body is also susceptible to infection. A hermit crab with no shell is also likely to die if it gets too hot or cold, because it has no way to insulate itself.
The most common illness a hermit crab may have that causes it to leave its shell is fungus. This fungus can attack the crab and make it so that it cannot move within its shell. It can also cause the crab to lose weight, which can further affect its health.
Another issue causing hermit crabs to leave their shells is stress. The harvesting and shipping of hermit crabs to pet stores is a very stressful process. They are often hungry, dehydrated and stressed when they arrive at the store. The employees usually don’t know how to care for them properly, which makes the situation worse. Hermit crabs are very sensitive to their environment and any changes can cause them to leave their shells.
When you notice your hermit crab is leaving its shell, don’t panic immediately. Sometimes it is a sign of molting, but most of the time it means that your crab is being irritated by something. This can be a sand or dust that is lodged inside of its shell, mites, fungus or even other hermit crabs. If you suspect any of these issues, put the hermit crab into a cup and isolate it. Provide it with a couple of good-fitting shells in the quarantine tank and place it into a clean, quiet and dark area so that it can settle back into its shell.
Hermit crabs are a shell-carrying crustacean, with more than 800 species worldwide, occupying empty scavenged snail shells to shelter their soft abdomens. This adaptation has greatly contributed to their evolutionary success, allowing them to access more habitats and food sources with less risk of predators.
A hermit crab that is out of its shell is most likely molting, but it could also be suffering from stress, a preference issue or an irritant. If the crab is molting, it will be too weak to move into another shell, and should be kept isolated until it has sufficiently hardened and regained energy. In the meantime, provide it with a larger bowl of water and an assortment of shells of varying sizes and styles.
The crab may have an irritant lodged inside its shell, which could be sand, mites or a fungal infection (a common occurrence with hermit crabs). It might have been displaced by another hermit crab, or it may simply not like its old home. In this case, make sure that the crab has plenty of other shells to choose from in its habitat by washing and sterilizing new ones. Make sure that they are slightly larger than the hermit crab’s former shell.
Providing hermit crabs with various shell shapes, sizes and styles should reduce the amount of fighting they do among themselves over desirable shells. It should also reduce their exposure to other hermit crabs, which can lead to scavenging or death due to bacterial and fungal infections. In addition, lining the habitat with silica play sand, soil or coconut fiber will help keep the substrate clean and dry; this will prevent fungus from growing in it, which is an irritant to hermit crabs.