Why does your hermit crab have a white eye?

If the eyes went white before the crab died, it is possible that the crab was having a problem molting. Molting is a strenuous process where the hard outer skin (called Chitin) of the hermit crab's body is shed to allow the crab to grow, much like many reptiles do. Many hermit crabs will start to lose a little of their color before they molt, and the area around the eyes can often go completely white before the molt.

It is also possible that the crab is not dead. The shed outer skin often looks like a still-living crab.

A good way to tell if you are looking at a discarded outer skin or a dead crab is to smell the place where the crab lives. Dead crabs give off a very, very distinctive fishy smell. If their is no smell, and the crab is easily accessible, pick up the crab by the shell on its back and look closely at the opening. If the crab is alive, it will in fact be all the way in the back of the shell, hiding behind the discarded skin. Donot attempt to remove the outer skin or possibly dead crab from its shell, and do not attempt to help in any way. If you cannot see far enough into the shell to tell for sure, and their is no smell, assume your crab is alive without further investigation. Unless their is an excessive stench, you may want to consider waiting a day before discarding a potentially dead crab to ensure it is, in fact, actually dead.

If the crab is not dead, or you are unsure, the best thing is to immediately return the crab to the position you found it, as well as the discarded outer shell. Hermit crabs usually eat most or all of their discarded outer skin to replenish the nutrients they need for the new skin.

If you have multiple crabs in your tank, and the crab was out in the open, consider trying to segregate the molting crab from the others (some crabs my try to steal the shed skin and eat it themselves). The crab will not be moving around much, so anything simple you can use to help protect and shelter the crab will work (at times, I myself have used a paper cup and the bottom of a plastic soda bottle). Don't forget to punch air holes for the still living crab.

You can also cut the TOP off of a 2 liter soda bottle, and place it down over the molting crab, with the lid off of course. This keeps the other crabs out and keeps air flow to the crab. Be sure to provide him with water dishes and some calcium and protein rich foods.