Sven Zacek / Otter (lutra lutra) eating Gudgeon (Gobio gobio) in Southern Estonia, January.

Michel Roggo / Bullhead (Cottus gobio) Europe

Remi Masson / European bullhead (Cottus gobio) camouflaged among rocks and aquatic plants, Ain, Alps, France

Remi Masson / Two European bullhead fish (Cottus gobio) hiding among rocks in small river, Ain, Alps, France

Remi Masson / European bullhead (Cottus gobio) on riverbed of small river, Ain, Alps, France, May.

Jussi Murtosaari / Gudgeon (Gobio gobio) in aquarium, Finland, July.

MYN / Niall Benvie / Gudgeon (Gobio gobio) Burgundy, France, April.

MYN / Paul van Hoof / Gudgeon (Gobio gobio) adult, The Netherlands, February. meetyourneighbours.net project

MYN / Paul van Hoof / Gudgeon (Gobio gobio) adults, The Netherlands, February. meetyourneighbours.net project

Juan Manuel Borrero / Illustration of threatened species of Spain : Blue whale (Balenoptera musculus), Brown bear (Ursus arctos), Spanish ibex (Capra pyrenaica hispanica), Bullhead (Cottus gobio), Iberian Rock Lizard (Lace...

Steve Nicholls / European bullhead fish (Cottus gobio) UK

Michel Roggo / Bullhead (Cottus gobio) Europe