Clownfish are able to count.
Clownfish are good at counting
Researchers have found that the fish can identify members of their own species from the amount of stripes on their bodies.
The orange and white creatures are depicted as friendly in the film 'Finding Nemo' but they are actually aggressive and will fiercely defend their homes from rivals.
Experts found that common clownfish, with three stripes, pursued their own kind and those with two stripes, although they did not attack those with one stripe or none.
Dr. Kina Hayashi, of the Okinawa Institute of Science and Technology in Japan, said: "Common clownfish attacked their own species most frequently."
Common clownfish usually form two white stripes at 11 days old - with the third following three days later - and Dr. Hayashi is convinced that fish who grow up with two-striped youngsters see similar ones as competitors to be driven away.