An abundant population of native Mediterranean killifish (Aphanius fasciatus) still thrives in the brackish waters of St George’s Lake on the Akrotiri peninsula, although in less saline waters in the area it is scarce and threatened by introduced populations of the highly invasive mosquitofish (Gambusia holbrooki). This video was recorded in Cyprus on the afternoon of 28 February 2018 by Dr Ian Winfield.