Common clownfish 'recognise own species by counting stripes'

Unlike the star of Disney's Finding Nemo, real-life common clownfish are not keen on sharing their home with members of their own species.

- Nicola Davis

Now researchers have discovered how the striped fish kick unwelcome guests out: by counting the stranger's vertical white markings.

According to previous research, the sea anemones that house common clownfish can also be a temporary home for other species of fish. However, common clownfish do not tend to cohabit with fish that have vertical markings like themselves, instead being more aggressive towards fish models painted with such patterns.

Now scientists say it is not just the presence of vertical stripes but their number that helps the common clownfish recognise its peers.