When Do Hermit Crabs Change Shells: The Importance and Reasons of the Process

Hermit crabs change their shells every 12-18 months. Generally, hermit crabs change their shells each year, a process that can take up to several weeks. The timing of shell changes usually varies depending on each crab, but it’s usually around 2-3 years old. So if you’re unsure when your crab is in the shell-changing phase, look at its shell – it should gradually grow and shrink.

Importance of Shells to Hermit Crabs

Hermit crabs need shells to protect their soft body from damage when fully grown and mobile. When they outgrow their old shell, hermit crabs molt into a new one – which can take up to two months. 

Watch your crab, as shell changes can signal health problems or an impending molt. Don’t be alarmed if you don’t see your hermit crab shell change for a while, though – they may be hiding it until the process is complete. 

Reason Why Hermit Crabs Change Shells

It Is Molting and Needs a New Shell

Molting is a natural process that most hermit crabs go through at some point in their lives. The hermit crab’s body tells its brain when it is time for the molting process, so there is no confusion or anxiety about it. When a crab changes shells, the old one is discarded and left behind on the seafloor – ready for another hermit crab to use! 

It Has Found a Better Shell

If you’re noticing your hermit crab leaving its shell more frequently, there may be an opportunity for it to find a better shell nearby! The new shell is specially designed to fit the crab’s needs for protection and mobility. 

The best time to find a new shell is when the old one starts to break down and fall off. So keep an eye out for your hermit crab, and help it find its new home by gently scooping it into a new shell!

It Can’t Find the Shell Even Though It’s There

When a hermit crab feels ready to molt, it will break open the old shell and start to change into its new one. The process usually takes around 10-14 days, during which the crab needs to excrete nitrogen to grow its new shell. However, hermit crabs can’t find their new shells even though they are correct before them – they keep looking for the old ones!

Problems With the Environment

Problems with the environment can be explained as follows:

  • Hermit crabs need new shells to avoid being preyed upon by more giant crabs. If their shell no longer fits them, they will eventually switch to using their leg muscles.
  • When molting, the hermit crab must shed its old shell to grow another. This process requires a lot of energy, and if the conditions in which the hermit crabs live change too much, they might not be able to find new shells or die from lack of food because they have no protective coverings on their body anymore.


When faced with new surroundings or obstacles, these hermits don’t always have a choice; they need to switch quickly into a shell that will protect them. This might mean abandoning an old shell altogether and starting afresh. For some hermits, this process can be traumatic as it disrupts the carefully accumulated mollusk debris inside the new home. 

Hermit Crab Shell Changing Habits


The shell-changing habits of hermit crabs vary depending on the species, but in general, they will start to change their shells around the time they reach sexual maturity. If you keep a hermit crab as a pet, it will probably change its shell when it reaches adulthood, although this is not always the case. Sometimes hermit crabs will choose not to change their shells.

Availability of Shells

Helping your hermit crab maintain a plentiful shell supply is easy if you’re aware of seasonal sales and discounts on new shell products. If you live in an area with insufficient new shells, your hermit crab may start to delay its shell-changing habit. 

The availability of new shells determines when a hermit crab will change its shell. Hermit crabs usually change their shells between April and October.

Importance of Switching Shells

Hermit crabs change shells quite frequently – even if you think it’s not a problem. Changing shells is a natural process for hermit crabs, but some individuals may be more interested in this change than others. If you’re one of these people, you’ll know when the time’s right because your crab will stop scavenging for food and start constructing new shell cells.

Sometimes the shell change can be prompted by a new environment or growth spurt. If your hermit crab isn’t changing shells, it may not be in danger, and you don’t need to worry. It’s essential to watch your hermit crab closely to spot when they are ready to switch shells. This process is gradual and usually happens over several weeks. So, be patient and wait it out – hermit crabs change shells!

Reason Why Hermit Crab Hasn’t Changed Shells in a Long Time

This can be a sign that your crab needs a new shell and can be a bit of a worry for those of us who aren’t experienced with shell-changing hermit crabs. However, don’t worry! You can do a few things to determine if your crab is healthy and needs a new shell. One way to check is to look for any signs of illness or injury. If you find anything out of the ordinary, it might be time to take your crab to the veterinarian.

Hermit crabs are usually quite active and change shells regularly, but sometimes they don’t want to switch shells. Providing a new shell or coaxing them into changing with some food rewards can be helpful in these cases. If the hermit crab doesn’t want to switch shells, it can hold on to its old shell until it grows too big or falls off. And as long as shell-switching is a regular occurrence for your hermit crab, you shouldn’t have any problems!

Possible Effect of Hermit Crabs Not Changing Their Shells

If a hermit crab doesn’t switch shells soon enough, it may become trapped in its old shell and die. If you’re unsure when your crab is ready to change shells, give him a gentle nudge – he should respond by removing his shell quickly! Be sure to keep an eye on your crab and change his shell when it’s time – this will help him survive and be healthy.