Remember, the habitat (or as many people call it, “crabitat”) needs to be able to hold 3 dishes, climbing toys, shelters, shells, and have space for the crabs to walk around. A 10–20 US gal (38–76 l) tank usually does nicely for 3 to 4 small hermit crabs. You may want to consider starting off with at least a 30 US gal (110 l) tank. A larger tank will allow more climbing toys and more space. Hermit crabs, when cared for properly, can live for decades and grow very slowly to the size of a baseball. The tank size will need to increase as the hermit crabs grow.
Select a lid with small air holes installed in it. If your tank has a mesh lid, you can cover it with plexiglass to prevent escapes. Hermit crabs need a humid environment, so this will also keep the moisture in the tank. Be sure to leave a little bit open at each end to allow for air flow.
Medium crabs (golf ball size) need at least 8 inches (20 cm) of substrate for molting. Small crabs (quarter size) need 6 inches (15 cm). Tiny crabs (often called “micros”, the size of a dime) need 4 inches (10 cm) of substrate. Examine the substrate carefully before putting it in the crabitat. Sift some through your fingers and check for insects. Be sure to smell it, too. Sand that smells moldy has probably been contaminated.
Remember that the inside of your crabitat should be like a mini-Caribbean island. It should have a moist, tropical feel to it. Keep the substrate at sandcastle consistency. You should be able to make a hole in it easily, but not get your fingers wet. Puddles of water or muddy substrate means you are misting too much. If you have a plastic crabitat with holes in the lid, place a warm moist towel over the lid to get an extra humidity boost inside. You should install a hygrometer to track humidity in a tank, which should be at 70-80% for hermit crabs.
When using a 10 US gal (38 l) tank, the best way to heat the tank is with an under the tank heater (usually referred to as a UTH). These are small pads that stick to the outside glass of the enclosure and usually raise the temperature up between 4 and 6 degrees. Try placing the unit on the bottom of the tank. Even with a thick layer of substrate the UTH will be effective. Heat lights work great on larger enclosures and can usually heat the tank to any temperature. A 40 watt light will do nicely on a 10 US gal (38 L) tank. Heat lights do dry out the tank very quickly, however, so you may have to spray the inside of the tank more often. Make sure that the heat source is placed on one side of the tank, and not in the middle. This is so the tank has a warm and cool side so the crabs can be around whatever temperature they prefer.
Hermit crabs cannot drink tap water. This water is treated with chlorine which can cause permanent blisters on the crabs’ gills. It’s a lot easier to have a batch of water ready to use for the next few weeks or so rather than having to make a small amount every day. Look for a conditioner that removes chlorine and chloramine and neutralizes heavy metals.
If you have very large and very small crabs living together, put pebbles at the bottom of the large crab’s water dish so a small crab can have a way to get out of it if it falls in by accident. Always make sure there is a way for the crabs to climb out of the dishes. Put a little bit of sponge, shells, or pebbles in the dish. [9] X Research source You can also make your own fresh, dechlorinated saltwater. Make 1 US gal (3. 8 l) of dechlorinated water using your water conditioner. Add 10 tbsp (170 g) of aquarium salt. Let the water sit overnight so the salt dissolves. Do not use table salt to make the salt water. It contains harmful iodine. Many crabs also drink salt water prior to molting. Providing salt water allows the hermit crab to choose what kind of water it would like to drink.
You can use coconut huts, ceramic flower pots, large shells, reptile caves, fish decor and many other things as potential shelters. Pieces of wood, Lego structures, cork bark, fake or live plants, rocks, large coral, barnacle clusters, and fish décor all make great climbing structures. Avoid using evergreen wood in the crabitat, as it annoys the hermit crabs. Try creating a second level to the crabitat by using a shower caddy stuck to the glass walls of the tank. Fill it with moss or coconut fibre. Add a branch to act as a ladder for the crabs to climb up. Prop up a large branch into a corner and drape it with fake plants so that it acts as a tree which the hermit crab will enjoy hiding in.
You may want to alternate between several different foods. Hermit crabs love to have variety in their diet. Small crabs will usually need about 1 small spoonful of food per day. Avoid any food that contains copper sulfate or ethoxyquin.
Try feeding grapes, bananas, blueberries, and apples. They love tropical fruits found in their natural habitat, like mangoes, papaya, and coconut. Avoid giving them citrus fruits, like lemons or oranges. All vegetables except for onions and scallions are great for crabs. They especially enjoy carrots, lettuce, and spinach. Try giving plain cereals, rice, pasta, unsalted nuts, and rolled oats as treats once per week. Many hermit crabs also really enjoy ground flaxseed. Provide small pieces of meat for your crabs on a daily basis. Hermit crabs love picking meat off of bones. Any type of meat will do: turkey, beef, duck, lobster, catfish, or grubs. Be sure the meat is unseasoned and doesn’t have any sauce, butter, salt, or oil on it. You can serve them raw or cooked.
Land hermit crabs need calcium to help their exoskeleton grow. It’s also important to help them molt.
Crabs also enjoy eating grass, oak leaves, and tree bark. Rinse them off with dechlorinated water and let them dry before you give them to the crabs. Be sure to look at the ingredients of what you are feeding them so you can avoid extra sugars and other unwanted items.
Make feeding and cleaning part of your daily routine. Feed your hermit crabs at the same time every evening, and then take away any uneaten food the next morning. You can keep dry food in the crabitat for 2 days, but be sure to remove any fresh food daily. Hermit crabs eat very little and in small amounts. To put it in perspective, most hermit crabs take a few hours to eat half a cheerio. So don’t think that your hermit crabs are starving, because they aren’t!
Your crab may start by doing a “taste test” of the food. It will put an antenna on the food, and then stick the antenna into its mouth. If your crab is interested in eating, it will pinch off small bits of food with its claw and then put it in its mouth. If your crab isn’t hungry, it may pinch the food but not eat any of it. In this case, put it down and try again later.
You can tell if a hermit crab’s shell fits if it can seal the opening of the shell with its large claw and armor leg (back left). As a general rule, land hermit crabs prefer shells with round openings. You can get inexpensive shells from craft stores. Another great place is online. Boil the shells for 20 minutes & drain them before putting them in the crabitat. If its legs stick out a bit and you can still see its eyes, the hermit crab will be on the market for a new shell. Simply drop some shells in the tank and the hermit crab will change when ready. You can dip the shells in salt water periodically to draw the crabs’ attention to them if you wish.
You should replace all the substrate every 6 months. Every month, take all the shells and dishes out of the crabitat and boil them in dechlorinated saltwater to kill any mold or bacteria.
Try to get your hermit crab to walk down your arm or hand and get into the water himself. If that doesn’t work, gently lift him by the shell and lower him into the bath. Always supervise a bathing crab. It can get really active after bathing, so even if it’s sitting at the bottom of the water at one moment, it might be scurrying out and getting lost in your house in the blink of an eye. Your drying off area can be as simple as a cardboard box lined with paper towels to absorb the excess moisture.
Even if your hermit crab knows and likes you, it may still pinch you if it becomes frightened. Be sure to handle the crab gently and carefully.
The trip to the veterinarian may be quite stressful for the crabs, so be sure to only take them only if absolutely necessary.
