Clownfish show off ability to count: Defending their territory like Pixar's Nemo

"Finding Nemo", an American animated blockbuster, was released in 2003. The movie received extensive worldwide recognition, earning an Oscar for the best-animated film. Its plot revolves around the story of a clownfish named Marlin, who embarks on an exhilarating journey to rescue his son from captivity. Nemo, the abducted fish, must learn to adapt to life beyond the confines of the coral reef.

The movie led to a significant rise in the recognition and popularity of clownfish. It's important to note that these fish, scientifically known as Amphiprion, belong to a genus of small, marine, perch-like fish from the Pomacentridae family. They are commonly referred to as clownfish or anemonefish. Remarkably, according to various scientific studies, these creatures exhibit the ability to count!

Following the international success of the movie, many parents were persuaded by their excited children to buy the characteristic clownfish, famously known as Nemo. Consequently, pet store owners quickly learned to refer to the common clownfish as Nemo to meet customer's expectations. Naturally, these fish are found in coastal waters, notably in tropical sea coral reefs. Other habitats include the Indian Ocean and the Pacific Ocean.

Unlike their reel-life characterization, clownfish are feisty creatures that fiercely guard their territories. This unique nature led to an interesting study by researcher Kina Hayashi from the Okinawa Institute of Science and Technology in Japan. The researcher discovered that clownfish have the ability to count, a skill they predominantly use to identify their enemies!

Research findings from Japanese scientists indicate that clownfish can count the stripes on their intruders' bodies. They do this to distinguish from different species that may encroach on their territory. The research was published in the "Journal of Experimental Biology", where the scientists revealed how they bred an entire school of clownfish to verify this theory.

The carefully controlled experiment aimed at confirming that the captive bred clownfish had never encountered representatives of other fish species. Subsequently, the experts decided to film the reactions of the bred fish to the introduction of other clownfish species in the same tank. The observations revealed that in most cases, the fish would initiate an attack upon spotting a clownfish intruder, particularly if it had three white stripes.