information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Flounder (Platichthys flesus)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.
Only coastal and marine records shown



The flounder has a roughly oval shape, with both eyes on the right side of its head and has a small mouth and pointed snout. The lateral line curves slightly around the pectoral fin. It has a smooth body except for some rough scales along the lateral line and a row of prickly humps along the base of the dorsal and anal fins. The caudal peduncle is long, accounting for about half the length of the tail. The topside colour is variable from dull brown to greyish-green, often with small orange spots, while the underside is white. The flounder grows up to 50 cm in length.

Recorded distribution in Britain and Ireland

The flounder is common to all British and Irish coasts.

Global distribution



A bottom dwelling fish living in inshore waters to depths of 50 m, Platichthys flesus can often be found in estuaries and sometimes freshwater.

Depth range


Identifying features

  • Oval in shape, up to 50 cm in length.
  • Small mouth, pointed snout.
  • Square-cut tail.
  • Topside colour variable from dull brown to greenish grey
  • Underside white.

Additional information

Identification of Plactichthys flesus is made more difficult by the existence of 'reversed individuals' in which the eyes are on the left side of the body. Hybrid individuals have been know to occur through interbreeding between flounder and plaice (Pleuronectes platessa) (Dipper, 2001).

Listed by

Further information sources

Search on:


  1. Dipper, F., 2001. British sea fishes (2nd edn). Teddington: Underwater World Publications Ltd.

  2. Hayward, P., Nelson-Smith, T. & Shields, C. 1996. Collins pocket guide. Sea shore of Britain and northern Europe. London: HarperCollins.

  3. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  4. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  5. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line]

  6. National Biodiversity Network (NBN) Atlas website. Available from:  Accessed 01 April 2017


This review can be cited as:

Pizzolla, P.F 2005. Platichthys flesus Flounder. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 16-08-2018]. Available from:

Last Updated: 22/04/2005