Pantodon buchholzi

Habitat: still waters such as swamps and creeks in west Africa, very much doing its own thing

We've all heard the saying 'If it ain't bust, don't fix it'. It turns out there's an animal that takes it to extremes.

Tens of millions of years ago, the African freshwater butterflyfish evolved a distinct body and lifestyle, and it has steadfastly clung onto them ever since, despite dramatic environmental shifts and changes in its own genes. It is one of the most compelling living fossils – species that have stayed the same for millions of years.

To find a butterflyfish, you must go to the central Congo or lower Niger, and keep a close watch on a still body of water. Insects will be skittering over the surface, and every so often one of them will vanish with a 'plop'. That is the butterflyfish at work."
New Scientist/read more