Lake Retba or Lac Rose (meaning Pink lake) lies north of the Cap Vert peninsula of Senegal, some 30km (18 miles) north-east of the capital, Dakar[1] in northwest Africa. It is named for its pink waters caused by Dunaliella salina algae and is known for its high salt content, up to 40% in some areas.Fish have adapted to the high salt content of the lake, having evolved ways to pump out extra salt and keep their water levels balanced.[8] The fish are approximately four times smaller than when living in a normal environment - this is known as salt water fish dwarfism