What you need to know about your Water, Sponge and Sand, for your hermit crab.
Hermits need regular drinking water all the time If you have an Ecuadorian crab, Coenobita compressus which a few pet stores sell you will need to also have a dish of sea salt water. They drink both. Most of the hermits sold in the US are of the type Coenobita clypeatus which drink for the most part regular people water. One thing they should not have is heavy chlorinated water. You can leave your water sit out over night and it will be good, as the chemicals do evaporate out of the water. It will make it de-chlorinated. All plant people know this. Some people recommend Stress Coat (a product you can buy for reptiles) for the bath but it really isn’t necessary if you just let your water sit and feed your hermits sea fan vitamins. We have been feeding our hermits regular water for 50 years and they seem to survive. Many of our customers have the same crabs they purchased from my parents store in OC years ago as children and still use tap water that has sit out for at least 24 hours. Often water straight from the tap doesn’t hurt them but be careful as it just depends on how much and when your City chlorinates their water. You can always go for the general de-chlorinator product or tap water conditioner found in aquarium shops for fish, if your over concerned.
The Ecuadorian crab, Coenobita compressus, bodies have adapted to this sea-shore existence by becoming able to metabolize the salt in sea water. They’ve adapted so well to their environment that they actually need sea water to live. Some recommend it and some wonder about it. If you do have this type of crab they probably need both types of water to drink. Sea Salt and Instant Ocean from and aquarium shop will give you the salt water you need. Table salt will NOT WORK. Salt In the water for a bath will not hurt any type of crab but to drink I don’t think that is the best idea for Caribbean Crabs (coenobita clypeatus). They do need minerals and Sea Fan is a vitamin which really works. It is full of sea salt, minerals, calcium and everything they need to be strong.
A regular natural sponge in the water keeps hermits safe from drowning in a deep dish of water. They do like to nibble at them once in awhile too, so having a sponge even if your dish isn’t deep can be a good thing. You can keep your sponge clean if it gets algae on it by cleaning it in chorine and then of course rinsing it over and over and then dipping it in boiling water to remove any left over chemicals. Just dipping it in boiling water works but it may still have a little green on it. Another good way is to put your water dish and sponges in the dishwasher, and even and real coral you may have (not sea fan). It really works. Be sure to dip them in boiling water after to make sure there are no chemicals left, just in case. The sponge also helps put some humidity into the air by providing a larger surface from which the water evaporates. Keeping their environment humid can be very important. Land hermit crabs have modified, stiffened gills which allow them to breathe air. They are GILLS, however, and not lungs, so are not able to breathe as we do. The air a hermit crab breathes has to be humid or water has to be present in their shell or the gills will dry out and the crab will not endure a long unpleasant death of suffocation which would be similar to a human's death by dehydration.
Your sand (Not gravel), can be beach sand but microwave it first to remove any sand flees. (If your under 16 ask your parent so do this). We sell play colored sand from a coral base and is good for hermits. You can also buy play sand from any hardware store which is not toxic and safe for all hermits. We do NOT recommend gravel as this is not their natural environment. If you get even the tiniest piece of gravel in your shoe you have to stop and get it out immediately. But if you get sand in your shoes from a walk on the beach, you’ll walk back to your car, no problem, with that sand in your shoes because it does not hurt. The same goes for hermits. If they get a piece of broken off gravel in their shell this could cut them and that could really hurt them. This is why we do not recommend or sell gravel.
Other objects for decoration in a corner do not hurt, shells, beach glass (smooth), coral, wood, are all fine for your hermits environment. Aquarium toys can also be fun for your hermits to play and hide.