If you have visited a large aquarium, you have probably seen the cool exhibits with little gobies (cute fish) and pistol shrimp. The pistol shrimp are essentially blind, and have a symbiotic relationship with the gobies. The shrimp dig the tunnels in which both live, and the gobies keep an eye out for predators. In some parts of Raja Ampat, you can look at the sandy sea floor and see a goby and a paired shrimp every few inches. Here are a few of the odd couples I got some photos of.
For more information on their symbiotic relationship, click here. Here is some footage of how the shrimp excavates as the goby keeps watch: