This fish rocks

Four-eyed fish (Anableps anableps) at Living Coasts in Torquay have been observed performing a behaviour that zookeepers think has never before been recorded. Sharp-eyed aquarists Tom Fielding and Sam Worthington videoed the female fish rocking from side-to-side, which appeared to attract the male.

Clare Rugg, curator of the Devon coastal zoo, has a theory: “One possibility is that the movement of the female fish is releasing pheromones into the water to signal that she is ready for mating. She maximises the spread of the pheromones by swaying her body from side to side so that the chemical signal is carried further on the ripples of water. We see her doing the rocking and after a while the males start to approach – perhaps once they have sensed the pheromones in the water.”

The behaviour has been observed several times by staff, who now hope that research can be carried out. Living Coasts is home to 38 four-eyed fish; the coastal zoo, part of the Whitley Wildlife Conservation Trust, is one of just a handful of zoos across Europe to keep them. Watch the video here.