The Shrimp and the Urchin

The oceans host many symbiotic relationships. In symbiosis, plants and animals live together in ways that benefit them and often others nearby. This is the story of the shrimp and the urchin.

Coleman shrimp (Perclimenes colemani) eat parasites they take from fish that come close to them in the western Pacific Ocean. These shrimp were not discovered until 1975, perhaps because they blend in very well with the sea urchins with which they have a symbiotic relationship. The picture shows the spotted body and striped legs of the Coleman shrimp surrounded by the striped tube feet of the fire sea urchin (Asthenosoma varium).

Coleman shrimp are known as cleaner shrimp because they remove parasites from fish. Most cleaner shrimp live in sea anemones, but Coleman shrimp prefer to live in fire sea urchins. The venom-tipped spines of the fire urchin do not harm the Coleman shrimp, and they protect them from potential predators. Meanwhile, fish infected with parasites approach the Coleman shrimp to have the parasites removed. The parasites are food for the shrimp, and the fish don’t eat the shrimp or the fire sea urchin because of its poisonous spines.

We see a balanced symbiotic relationship among various species of ocean creatures. The shrimp and the urchin, along with many fish that benefit, are just some examples of symbiosis—where different plant and animal species depend directly on each other. In many cases, a species could not survive without this mutual relationship. This is another sign of design in living creatures, and design points to a Designer.

— Roland Earnst © 2025