Vet Q & AWhat water do hermit crabs drink? Is tap water safe for them?
Hermit crabs need two types of water. Fresh and saltwater. Hermit crabs also cannot drink tap water. This water is treated with chlorine which can cause permanent blisters on the crabs gills (yes they have gills) which will be very painful for the hermit crabs. For this reason all water (including drinking and misting water) must be unchlorinated. Buy a small bottle of tap water conditioner in the fish section of your pet store. Follow the instructions for making a gallon of water. 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. When choosing a conditioner, do not purchase "Stress Coat" as this is used strictly for bathing your crabs and keeping fish only. Look for a conditioner that removes chlorine and chloramine and neutralizes heavy metals. Do not get a conditioner that stimulates a slime coat, other than for baths. After that, you have a batch of freshwater. Now simply make another batch of water and add some aquarium salt into the mix. Usually about 8-10 tablespoons of salt is enough. You may hear that only exotic species of hermit crabs need salt water, but this isn't true. All hermit crabs including the purple pincer (Coenobita clypeatus) need this. Many crabs drink saline water for hours prior to molting. And their shell water supply has a specific balance of iron. Providing salt water allows the hermit crab to choose what kind of water it would like to drink. Let the water sit overnight, so it comes to room temperature and the salt dissolves.
Updated on September 24th, 2025
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