Aquatic vertebrates with fins (for swim­ming) and gills (for breathing), which rep­resent an important source of food. At present, more than 30,000 species are known (as many as all other vertebrates put together). Most fish live in the seas and oceans, at varying depths. Freshwater fish are much less numerous. Some fish, such as eels and salmon, are migratory, spending part of their life in the sea and part in fresh water.

Fish are classified into two broad groups, according to their skeletons: carti­laginous fish (sharks, rays, dogfish, skate) and bony fish (the vast majority). Several basic body shapes can be distinguished:

·        round, adapted to swimming in the open water (herring, cod, salmon, mack­erel, carp, pike, etc.) - these are the most numerous;

·        flatfish compressed vertically, with the eyes on the darker dorsal (upper) surface
(e.g. skates and rays) — the ventral (lower) surface is white;

·        flatfish compressed laterally, with both eyes either on the right side of the head
(e.g. plaice, flounder, dab, sole) or on the left (e.g. turbot, brill), the blind side usu­ally being without pigment;

·        elongated and snakelike (e.g. eels).

Buying fish There are three main factors to consider when buying fish: its availability (depending on the season), its freshness, and the percentage of waste. The season is less important now than it used to be, because fish caught off the Af­rican or northern coasts are sold almost all the year round. However, it is always bet­ter to eat fish in season: it tastes better and is cheaper.

Freshness is the most important quality offish. Fish is subject to speedy decay by bacterial action and often causes food poisoning if it is not absolutely fresh. It is at its best when first caught, but the speed of modern transport and the excellent methods of preservation mean that fish can be enjoyed far from the fishing grounds without loss of flavour.

When buying Fish the following points should be looked for to Ensure Freshness.

EYES.

Should be Bright, Full and not Sunken or Cloudy.

GILLS.

Should be Bright Red in colour with no Bacterial Slime.

FLESH.

Must be Firm, Translucent and Resilient so that when Pressed the Impression goes quickly. The Fish must not be Limp.

SCALES.

Should be Flat, Moist and Plentiful.

SKIN.

Must be covered with Fresh Sea Slime or be Smooth and Moist with no Abrasions, Bruising or Discolouration.

SMELL.

Should be Pleasant and of the Sea not Ammonia or Sour.

A selection of fish recipes tried and tested at Cooks Reference.