Blue Knuckle Hermit Crab

Care Summary

The Blue Knuckle Hermit Crab is a mid-size hermit with vivid blue joints that makes a solid addition to the cleanup crew in reef tanks of 30 gallons or more. It is generally reef safe with corals and most fish, but like all hermit crabs it is an opportunistic shell stealer, so keep a selection of appropriately sized empty shells in the tank to reduce the likelihood of it evicting your snails. They can be kept in small groups but provide enough space, food, and shells to reduce competition, as shell-related fights between hermits can result in injury or death for the loser. They are omnivorous scavengers that will eat algae, detritus, and leftover food, but supplement their diet with sinking herbivore and carnivore pellets a few times a week for best long-term health.