Good on you for wanting to give your hermit crabs another playmate. It’s recommended that a hermit crab enclosure contains at minimum two crabs of each species. This makes sure that everyone stays happy and social.
If you need to correct yourself and buy another, or a few more, hermit crabs, there is always the fear of conflict. What happens if one of your crabs does not like his or her new playmates?
I wondered the same thing, so I talked to a few hermit crab adopters. They have a step-by-step process which I know will keep your hermit crabs civil and accepting of their new tank mates.
Step 1: Make Sure Your Crabitat Can Handle New Crabs
Like most pets, your hermit crabs need plenty of space to roam, climb, crawl, and dig. Depending on their size, each of your crabs needs a certain amount of space to not feel cramped. You may have done that already, but throwing a few more crabs into the mix may overload your crabitat. The last thing you want is your little crustaceans to feel restricted!
So, the question stands. Can your aquarium handle extra hermit crabs?
To answer that we need to know if you have a suitable-sized enclosure. I have a size chart in this article for how many crabs fit in a 10-gallon tank, 20-gallon, and so on. Make sure you check that table so you know whether or not you have room for a new crab buddy. If not, you’ll need to upgrade to a larger tank.
The next thing we need to keep in mind is your tank’s interior. Now that you are sure that you have enough space, you need more hiding spots, shelters, food, and water for extra hermit crabs.
The top priority is hiding spots. Each crab needs enough room to feel safe and secure. Without it, they will constantly feel stressed and not live for very long. A great hiding spot could be a hollowed-out log or coconut, plastic greenery, or foliage (all of which are available at a pet store).
The next thing you need to worry about is food and water. Your crabitat needs freshwater and saltwater bowls deep enough for your largest crab to submerge. Without it, your pet cannot clean itself after a deep burrow or long molt. It encourages good hygiene while keeping your crabs from going thirsty.
Food is pretty straightforward. More crabs need more food. The little things eat very little, but make sure they have access to a well-balanced diet.
Step 2: Set Up An Iso. Tank For The Newcomers
An isolation tank (iso for short) may sound like an unpleasant experience for your new hermit crabs, but it may be just what they need. Chances are that your hermit crabs were living in less than ideal conditions at the pet store, boardwalk, or wherever you bought those creatures. The transition from there to your crabitat can be a stressful experience, which means you need to do everything you can to make them feel at home.
The last thing your hermit crabs need are some judgmental tank mates as they destress and get a feel for their new environment. A great solution to this is to set up an isolation tank.
This should be a smaller tank (10gal is ideal) filled with everything your crabs need to destress. It’s a good idea to set this up correctly as it will come in handy while dealing with molters later on. Fill your isolation tank with at least 6 inches of coconut fiber and play sand mix. You want it to be moist enough to be shapeable, just not dripping water. Along with that, you’ll need two bowls: one for freshwater and the other for saltwater. Both need to be deep enough for your crabs to submerge entirely.
Next, come food and shelter. Your iso tank will need a food bowl that’s frequently filled with healthy snacks. Along with that, it will need a certain amount of space for your hermit crab(s) to hide (depending on how many you plan to house). For shelter and food, however, I want you to do something a little different. I want you to use decorations from your main hermit crab tank with your original crabs. Doing so will bring along the scent of your hermit crabs, which will make your new crabs get used to their eventual tankmates’ scents. Similarly, I want you to regularly swap food bowls between your iso tank and regular tank. Be sure to rinse them of any leftovers before doing so. A small scent will linger, getting your crabs used to one another’s scent. This may seem insignificant, yet it makes the introduction much smoother because your hermit crabs will already be vaguely familiar to one another.
Step 3: Allow Them To Molt & Destress
Now that you have your isolation tank setup, it’s time to add your new hermit crabs. By now you may be thinking this is a bit complicated just to get new hermit crabs, but trust me. It’s the best way to break the social hierarchy in your current crab tank and allow these new guys to fit in just fine.
Before they can do that, however, they need to recover from the pet store. I mentioned before that your crabs will most likely be in bad shape when you first buy them. They need time to recover and be ready to make a good first impression with your hermit crabs, which is what the iso tank is for.
When I first bought my two hermit crabs, they did 3 things to recover from the pet store: burrow, change shells, then molt. This happened for about 2 months, now they are happy and active. Your iso tank will act as a safe place to get them through that awkward stage that all new hermit crabs go through. It’s especially handy because hermit crabs are vulnerable while they molting. Their exoskeleton-less skin is very fragile and quite tasty for stronger hermit crabs, which runs the risk of your crab getting eaten. I don’t know about you, but I can’t imagine a worse scenario than your new hermit crabs getting eaten by the older ones.
Anyways, you need to give your new crabs a few months in the iso tank before moving them to the main tank with your other crabs. You’ll know it’s time to do so when they’ve changed their shell, molted for a few weeks to a few months (it depends on their size), and are more noticeably active around the iso tank.
In the meantime, you need to keep the iso tank as clean as your main tank. Regular spot cleaning, switching the food bowls, and making sure they are living in a humid environment is ideal for getting your hermit crabs ready for their big transition.
Edit: I forgot to mention that your iso tank needs plenty of unpainted shells! Go for at least 2 slightly larger shells and one that is slightly smaller per crab. It is rare, but some crabs change into a smaller shell before molting.
Step 4: Clean The Main Tank
Now that your hermit crabs in iso are ready for their new home, you need to make sure it’s neat and tidy. You wouldn’t invite someone over if your house was a pig style, and the same goes with your hermit crabs.
Good pet owners spot clean their crabitat every few days of any hermit crab droppings, uneaten scattered food, etc. It’s apart of keeping their hermit crab enclosure clean and livable. On top of that, it’s recommended that crab owners do a more thorough cleaning of their tank every 3-5 months. It’s especially important to do this right before you transport new hermit crabs to your enclosure.
It’s pretty straightforward. You need to replace your substrate, thoroughly wash the tank’s glass, disinfect decorations and shells by boiling them in water, and so on. You want your tank to look just like new! Just make sure that the crabs already living in the tank aren’t molting. It’s a very bad idea to disturb a molting crab.
You must move your new hermit crabs into a very clean and stress-free environment, which makes cleaning your main tank very important. I would wait a few days for the current tank’s residents to calm down after a stressful cleaning process, then introduce your newly purchased crabs.
A very good deep clean will rid your crabitat of bacteria, any sort of infestation, etc. All of which you do not want your new and fragile hermit crabs being exposed to. Doing so will make their transition from the pet store to the iso tank, and their main tankless enjoyable and very stressful.
Step 5: Place a few items from the iso tank in your main tank.
I used this tactic when my brother didn’t want his hermit crab anymore. I took a few items from this new crab’s tank and put it in my tank with my three hermit crabs. Right away, they went to the items and sniffed them with their antennas. My crabs knew right away that those items smelled of a new hermit crab, and they wanted to investigate.
The point in doing this is to get your hermit crabs desensitized to this new smell. This will avoid any aggravation and cause less mayhem when you add the new crab. Your old crabs will be used to their scent and not make such a big deal of it.
So, throw a few things in the tank and wait a few days. This is the most important step so make sure you don’t skip it.
Step 6: Add The Crabs & Observe
After this month-long process, you are finally ready to introduce your new crabs to their tank mates. Take each crab from the iso tank and gently place them in your main tank with the rest of your hermit crab family.
Now, keep an eye on your hermit crabs. It’s a good idea to gauge any interactions between any newbie and senior crabs for the first few days. You’ll be sure to see some “antenna fights” leg sparring matches, and other territorial behavior, all of which are natural to hermit crabs. Your crabitat is restructuring the chain of command, which can take a few days. As long as your tank has plenty of spots for each crab to call their own, do not worry about it! Your crabs will love their new home and get along just fine with their tank mates.
Some Hermit Crabs Should Not Be Put Together
Even with a well-executed introduction between two hermit crabs, sometimes certain hermit crabs do not get along. This has to do mainly with what subspecies of hermit crabs you’re forcing to mingle and the size of each crab.
I mentioned before how hermit crabs need a species buddy. For every Ecuadorian in your tank, you need another one for it to feel like it has a friend. The same goes with every purple pincher, strawberry, etc. (these are different types of hermit crabs). Before buying more hermit crabs, think about the species you want to buy and how many. If one hermit crab is left species-buddy-less, he may not live very long.
Another deciding factor is the size of the new hermit crab. There’s always a chance that the senior hermit crab will not accept a new one, especially if there is a major size difference. A jumbo hermit crab may even eat micro hermit crabs! It’s best to only introduce new hermit crabs that are of similar size with your current crustaceans.
Beware of Post Purchase Syndrome
If you just bought your hermit crab and plan to introduce him or her to the rest of your crustaceans, pay attention.
Post Purchase Syndrome (PPS) is the term to describe why a newly-bought hermit crab may suffer health problems and even death. All hermit crabs are wild-caught, which means they went through a tedious process to get from their home in the tropics to your crabitat. This can cause a buildup of stress which affects their health later on.
This disease makes placing your crab in an iso tank very important to help your crabs adjust to their change in lifestyle. While your newly-bought crabs are in their isolation tank, keep an eye on them for any peculiar behavior. They may have PPS. For more information, check out The Hermit Crab Association’s article on PPS.