Hermit crabs and snails are usually the first janitors that aquarists place in their aquariums because they are some of the best animals to have for controlling common algae problems.
About Hermit Crabs
Did you know that hermit crabs are scavengers? Yep, most species will eat just about anything they can find. For this reason, they make ideal cleaners for a reef tank, as long as you choose a Reef Safe Hermit Crab.
Properly chosen hermit crabs should have no negative impact on a reef system. In fact, they are solely beneficial. Small species that do not grow more than a couple of inches in size are most desirable, as they usually do not disturb other tank life, and they are able to get into tiny cracks and crevices where algae grow that larger hermits cannot access. They can also access spaces under rocks and corals where detritus or debris accumulated to remove it.
Large species such as the Anemone Carrying Hermit (Dardanus pedunculatus), Yellow Hairy Hermit (Aniculus maximus) and Halloween Hermit (Trizopagurus strigatus) are undesirable as reef janitors, as they may cause unwanted damage to your reef system. These types of hermits can disrupt tank life by climbing on everything, and because of the large clumsy, bulky shells they live in, cause the toppling of rockscape arrangements and the moving of corals. Besides, they may attack or eat other tank inhabitants. If you desire to keep large hermit crabs, do so only in a tank of suitable environment and size, and remember they will outgrow their shells. You need to provide them with new housing (larger shells) as they molt and grow, otherwise, they may attack other shelled animals to get a new shell. One commonly imported species that has this trait is the Clibanarius vittatus, most often sold as the Striped Hermit Crab. Do you need shells for your hermit(s)? Here are a few suppliers you can check out.