How to choose fresh fish at a counter or market

Judge fresh fish with your eyes and nose before you ask the price. At a counter or market, the most reliable signs are the eyes and gills of whole fish, the texture and sheen of the flesh, and the condition of the display around it. Fillets and steaks are harder to judge because the telltale parts are missing, so the questions you ask and the way the fish is kept matter as much as what is on the ice.

Decide what you plan to cook before you go. A mild white fish, an oily fish and a shellfish each have different signs of quality, and a good seller can point you toward the right cut for your recipe. Buy on the day you plan to cook or the day before, so the fish spends as little time as possible between the counter and your pan.

Judge whole fish by eyes, gills and skin

Whole fish should have clear, bright eyes that look full rather than sunken or milky. Cloudy or sunken eyes suggest the fish has been out of the cold for some time. Gills should be red or pink and moist, while gray or brown gills point to a fish that is past its best. Skin should look glossy, with scales intact and firmly attached. Fresh fish normally has a thin, clear layer of slime, so do not reject a fish just because it feels slippery. The warning signs are slime that looks milky, cloudy, yellowish or sticky, or scales that come away easily, which suggest poor handling or age.

Look at the body too. The belly should be firm and not swollen or split, and the area around the vent should look clean. If the seller allows it, look at the underside of the fish, since bruising or discoloration often shows there first.

Check fillets, steaks and shellfish

Fillets and steaks should look moist and have a clear, even color. Check the edges for drying or browning, and look for gaps where the flesh has separated into segments. Flesh that looks dull, gaping or sits in a pool of liquid may be past its best. Ask the seller to press a piece for you, or press it through the wrapping where the counter allows: fresh flesh springs back and leaves no dent. Smell the fish as well. It should smell of clean sea water or hardly at all, and a sharp ammonia or sour smell is a clear reason to choose a different piece.

Shellfish follow different rules. Live clams, mussels and oysters should be tightly closed or should close when tapped, and shells that stay open are a reason to leave them behind. Live crabs and lobsters should be active when the seller handles them. Ask whether shellfish is sold live or already shucked, because the guidance for each is different, and do not buy anything you cannot confirm is in good condition.

Oily fish such as mackerel and sardines can deteriorate quickly once they are out of the cold, so examine them even more carefully and plan to cook them the same day. Lean white fish shows its condition mostly in the flesh, which should look translucent and feel firm. Ask for a thicker cut if you plan to grill or roast, because thin, delicate fillets flake and break under high heat and suit quick pan cooking better.

Ask the seller the right questions

Ask when the fish arrived and where it came from. A good counter will know which port or boat a fish came from and which catch came in that morning. Ask whether a fish was frozen before it reached the counter. Previously frozen fish is not a problem by itself, but it changes how quickly you should cook it and how you judge its freshness, so it helps to know.

Ask the seller to clean or fillet a whole fish if you want that done for you, and ask for the head and bones if you plan to make a stock. Ask which cut suits your method. A seller who can explain why a particular piece is good that day gives you more confidence than one who simply points to the nearest tray. Ask for the purchase to be wrapped in paper or a sealed bag.

Read the counter and the way it is kept

The display is evidence in its own right. Fish should sit on fresh ice or in a chilled case, kept at about 40°F (4°C) or below. Look for ice that is clean and drains away rather than sitting in standing meltwater, and for trays that are not overcrowded. Fish that lies in direct sun or on a warm surface is not being kept properly. A clean counter and a steady supply of fresh ice are good signs that the shop takes handling seriously.

Notice the staff too. People who handle fish with clean hands, clean knives and boards, and who keep the scale and display tidy, are showing habits that matter once the fish leaves the counter. If the counter looks neglected, it is reasonable to wonder how the fish was handled before it arrived.

Trust the counter as well as the fish. If the staff are unsure about the source or the handling of a piece, choose another. Buy the fish last on your route, and if the trip home is long, ask for it to be packed on ice. Once you are home, refrigerate it promptly, since perishable seafood should not sit at room temperature for more than two hours.