Steinitz's shrimp-goby (Amblyeleotris steinitzi) and an alpheid shrimp (Alpheus sp.) at the entrance to their burrow. Steinitz's shrimp-gobies are always found in a mutualistic association with an alpheid shrimp. The near-blind shrimp builds and maintains the burrow, while the goby guards it. When outside of the burrow the shrimp will rest one of its antennae on the fish, which will quiver if it detects danger. Steinitz's shrimp- goby grows up to 8 centimetres in length and is found in sandy areas near coral reefs in the Indo- Pacific region. Photographed off Indonesia.