Nature’s Most Iconic Duo: Anemone & Clownfish
(clownfish & a sea anemone)
You probably remember where Nemo and Marlin lived in ‘Finding Nemo’– That’s right, they lived inside a sea anemone. However, did you know that the animated description of two clownfish living inside a sea anemone is not just for movie aesthetics, but is rather a depiction of one of the most marvelous symbiotic relationships in nature?
So what’s a symbiotic relationship? A symbiotic relationship (or symbiosis) refers to any long-term biological interaction between two different organisms. Such relationships can either be parasitic (one side benefits at the expense of another), commensalistic (one side benefits while the other side neither benefits or is harmed), or mutualistic (both sides benefit). The particular symbiotic relationship clownfish and sea anemones have is one of mutualism.
First, let’s look at what benefits the clownfish gets from being in a symbiotic relationship with sea anemones. Clownfish have a thick mucous layer that makes them immune to the sea anemones’ toxic sting, so if a predator approaches, the clownfish is able to hide within the tentacles of the sea anemone for protection. Anemones also provide a safe location for the clownfish’s eggs, where clownfish often lay their eggs on rocks close to a sea anemone for protection from predators. In addition to that, clownfish often feed on the dead tentacles and food scraps of the anemone.
Remember, this is a mutualistic relationship, so there must be something the sea anemone gets from clownfish as well. Turns out, there’s a lot. First, the clownfish's waste provides the sea anemone with many essential nutrients such as nitrogen. Adding onto that, clownfish also help clean the sea anemone, chase off animals that prey on sea anemones (such as the butterfly fish), and provides better oxygenation to the sea anemone’s tentacles by swimming around. Recent research shows that clownfish may also help fertilize the sea anemone with their ammonia-rich waste products.
Looking at how two seemingly simple organisms can live in such a harmonious mutualistic relationship, we as humans, can try to live in such similar mutualism with other organisms around us by reducing pollution.