What the body tells you first

Start with the eyes. A fresh fish has eyes that are convex, clear and bright — they sink and cloud within a day or two of death, and nothing hides that. Next look at the gills: lift the flap and check the colour. They should be a vivid red or deep pink; brown or grey gills mean the fish is past its moment. These two checks take ten seconds and tell you almost everything.

A market stallholder handing over a wrapped cheese
FIG. 02A cheese is chosen by the stall rather than the label; the affineur decides when a wheel is ready to go out.

The skin and scales come third. Scales should lie flat and glisten, not sit dry or peel away at a touch. On a skinned fillet, look for translucency — fresh white fish has a slight sheen and the flesh holds its structure; press it gently and it springs back rather than leaving a dent. If the flesh is separating along its natural flakes before it has ever been cooked, it has been stored too long.

Why smell is the last thing to trust

Smell is what most people check first at a fishmonger's counter, and it is the least reliable signal. A truly fresh fish smells of cold seawater — clean, faintly mineral, with very little odour at all. The "fishy" smell that people fear is trimethylamine, a compound produced as bacteria break down the fish; by the time the smell is obvious, the fish is already well into decline. But the absence of a strong smell does not prove freshness — a fish kept very cold may have little odour and still be older than you want.

The practical rule: smell confirms what your eyes have already told you, nothing more. If the eyes are clear and the gills are red, a faint smell is irrelevant. If the eyes are sunken but the counter smells pleasant, trust the eyes.

A baker sliding loaves into an oven
FIG. 03Loaves go in by hand and come out by colour; the baker reads the crust rather than the clock.

The fish that is already cut

Fillets offer fewer clues than whole fish, which is why fishmongers who fillet on the premises are worth finding. With a fillet, you rely on colour, texture and the condition of any remaining skin. Ask when it was cut — and if the counter staff can't answer, that is information too. Whole fish are harder to fake. A fish that was landed two days ago and filleted this morning is not the same as one that was filleted two days ago and has been sitting since.