Never use plastic tanks, as they don’t hold heat or humidity well. Jumbo hermit crabs require about 5 gallons (19 L) of space per 1 crab.
For land crabs, leaf litter and bark make a nice addition to your substrate but are not necessary so long as your tank has a base of sand and eco earth.
Swap out the initial shells for bigger ones as the crabs grow larger. Never use painted shells—they are dangerous and can be toxic to your crabs. Purchase branches and vines at pet supply stores or dollar stores for the crabs to climb on. Avoid any conifers and do not ever use metal inside the tank.
Purchase UTHs from pet stores or online suppliers.
Keep an eye on the temperature daily. The temperature at the cooler end of the tank should be about 70–72 °F (21–22 °C), and up to 82 °F (27. 8 °C) at the warm end. Although nighttime temperature dips are normal, tank temperature should never remain at 72 °F (22 °C) for long periods of time.
Don’t set the tank in direct sunlight. A glass tank will amplify the heat of the sun and can overheat very quickly, which can cause heat damage and illness to your crabs. If your crabs get sufficient daytime light, you can skip the tank lights. Install UVB bulbs to provide both light and heat for your crabs. This is a great option if you’re having trouble getting the tank temperature hot enough. If you need to heat your crabs at night, use bulbs that don’t release UV rays.
Give your crabs chopped coconuts, papayas, mangoes, and any fruits that are common in their native habitat. For meat and seafood, you can serve them raw or cooked and with or without bones. Just make sure there is no butter, salt, or sauce on them. Always place meat into the habitat at night and remove it in the morning to prevent flies or scavengers.
Keep your habitat away from pets and areas where you use cologne, hairspray, and room deodorants.
Both water dishes should be free from ammonia, chloramines, and chlorine. Chlorine will blister your crab’s gills. Always use a water conditioner that removes chloramines and heavy metals, as many homes have copper pipes and hermit crabs are especially sensitive to copper. Make sure the water dishes are at least as deep as your largest crab. It is not true that they will drown. Tupperware bowls or small paint trays work well. Give your smaller crabs a way to climb out of the bowl, such as small glass pebbles or uncoated river pebbles.
Crushed coral is also a suitable substrate, although it’s typically a more expensive option. Make sure the eco earth is dry when you mix it into your sand to prevent the substrate from waterlogging.
Pour {{convert|1/2|cup|mL|adj=on|| of tank moss across the substrate to increase moisture. You can also place the cup into the tank to give your crabs a moss pit to hide in. Never use peat moss. Don’t use sponges—they harbor bacteria and can make you and your hermit crabs sick.
Purchase pre-mixed saltwater from pet stores.
Buy pH paper and peat moss from pet stores.
Purchase both ammonia and nitrite testing papers from pet stores, big-box suppliers, or online stores.
Hydrometer scales read “specific gravity,” which is the ratio of the liquid’s density to the water’s density. Make sure replacement water is the same temperature as aquarium water. Don’t alter specific gravity more than 0. 001 per day. Anything more can cause shock to your hermit crabs. If necessary, adjust salinity over the course of 3 to 4 days.
