Figure 17.6 Habitat mutualist. The alpheid shrimp (Alpheus randalli) digs a burrow that it shares with a fish known as the pinkbar goby (Amblyeleotris aurora) in the waters off Indonesia. In exchange for this habitat, the goby allows the shrimp to place an antenna on its body so that the shrimp can feel the goby twitching when it sees an approaching predator.

Photo by Jim Greenfield/imagequestmarine.com.