Halocaridina rubra is the species of shrimp used in EcoSpheres. These shrimp are diminutive, reaching approximately 3/8 inch in length, and have pinkish bodies. Within the EcoSphere, Halocaridina rubra eat brown bacteria and algae.
The EcoSphere is an example of a closed ecosystem capable of sustaining itself for years under optimal conditions. Light that penetrates the glass is used as energy by algae, which is in turn consumed by Halocaridina rubra. The algae also produce oxygen for the environment, while bacteria decomposes the waste matter of the shrimp. In nature, Halocaridina rubra is found in brackish waters around the Hawaiian islands.