What is a Fluke or Flounder?

The common flounder or fluke, which can be found all round our coast in areas of sandy or muddy sea bed, is a remarkable creature. It starts life looking like any other baby fish, swimming upright with an eye on either side of its head. After a few days, it begins to lean sideways and sink to the sea bed; the left eye starts to migrate round to the right side of the face and by the time the left eye has completed the migration, the flounder is swimming flat with both eyes uppermost.

The ability to swim flat, combined with the capacity to change skin coloration to suit its surroundings, enables the flounder to lie concealed in sand or mud and prey on passing marine worms, sandeels and small crustaceans. Flounders tend to feed close inshore and are generally the first fish to be carried up estuaries by the flood tide. At slack water, flounders wriggle into the mud in the shallows to prey on their favourite food, peeler crabs, while they wait for the tide to turn.