Hermit crabs love to climb and have a knack for escaping their tanks. So, make sure that the tank you purchase comes with a lid, and keep the lid tightly shut once the crabs are inside!
As your collection increases, if you’re going to house more than 3–4 crabs in your tank, or if you’re caring for jumbo hermit crabs (not recommended for beginners), you will need a 20 US gal (76 L) tank. To avoid overstocking a larger tank, avoid keeping more than 6 purple pinchers in a 20 US gal (76 L) tank. Remember that they’re gonna grow and you’ll need to provide enough shells, food, and terrain for them to be happy.
Home-improvement stores and plant nurseries may also sell coconut coir. Coconut coir is harvested from the fibrous middle of the coconut shell. In stores, it’s typically sold as a dried brick that you’ll need to break apart before mixing with sand. It’s important to change the sand in the tank on a monthly basis.
You can purchase driftwood and plastic rocks at most pet stores. Pet stores should also sell genuine shells. Or, if you live near the ocean, take a walk along the shore and collect the items yourself.
Unlike many other species of crab, purple pinchers don’t spend much time digging.
Hermit crabs can become possessive over shells, and may even fight over an especially popular one. Try adding additional shells that look like the popular one to prevent future fights. When you provide new shells, wash them in hot water before adding them to the tank.
Hang a thermometer over the edge of the cage so you can easily check on the temperature from time to time.
If the humidity falls below 70%, use a plastic spray bottle to spray 10–12 bursts of dechlorinated freshwater into the tank. This will raise the humidity level. If the humidity rises above 80%, remove the top of the tank and place a sheet of mesh over the opening. This will allow the humidity to leave the tank.
You can clean the tank with the crabs inside as long as they don’t try to escape. If they do, pull the crabs out of the tank and set them in a second tank or a glass container that they can’t climb out of. Throw away old substrate and replace it with a new blend only if it becomes oversaturated and starts to mold. Do not use bleach when cleaning the tank, as it can be harmful to the crabs.
Set the feed dish at least 3–4 inches (7. 6–10. 2 cm) away from the 2 water dishes, so that the feed doesn’t get wet.
You can give the crabs the insects and fruit at the same time, or space them out by a few hours. Don’t give an individual crab more than, for example, a third of a banana. Most pet stores sell live insects that you can feed to your crabs. Crickets are a cheap, popular choice.
Dump out the old water and replace it with new water at least twice per week. So that your crabs don’t accidentally drown in the water, lean a 4 in (10 cm) stick or other object inside the dishes so crabs can easily crawl out.
