Blue legged hermit crab.
A "mostly" herbivorous addition to a reef tank popularly utilized to help control excess algae growth. They are collected in the Caribbean and adjacent areas. The "blue knuckle" hermit crab, a larger, more expensive cousin hails from the pacific ocean. It costs more. Thus, I do not have one to photograph.
Retail cost?
Caribbean blue leg hermit..$.79..Pacific blue knuckle hermit crab...$10
