How to Check for Good Quality Fish

Whist it is great to know how beautiful fish should look like if you are lucky enough to have a Master Fishmonger in your town or village, or indeed a well-established, high-end Fishmonger, some of us are not afforded such luxury and have to source our fish from other outlets, which at times could be, rather unsavoury.

So, how do we know what we are buying is “good, bad or ugly”? Well, don’t worry about the ugly, as beauty is in the eye of the beholder. Some say, a Monkfish is an ugly brute. I think not, and it’s certainly in my top 3 favourites for tasty, chunky, pure-white meat. So, let’s focus on the good and bad, and some of the in-between.

Good, yes, most of us know that a fish should look bright and shiny, with scales intact and no damage. But do we know enough about quality and condition to detect whether that shine comes from the natural moisturizing slime of the fish, or is it tap water giving the effect of shiny fish? Slime on fish is a natural phenomenon, it helps fish to glide through the water. It helps to prevent dehydration. It’s perfectly normal. Some fish have a much more pronounced slime: Lemon Soles, Skate Wings, Turbot, Halibut all have “gooey” type slime. Mackerel family fish (Scombridae) for instance, have very little slime. We must not confuse the slime this with is bacterial slime, which is when the fish are seriously deteriorating. This type of slime will be mustard yellow and give off an unpleasant odour. Remember, fresh fish should have little smell or a wonderful fresh smell of the sea.

When you go into your fish outlet store, you are not generally going to be able to pick up the fish to smell it and prod it, so we need to use our eyes. We need to be thinking along the lines of Her Majesty’s Coldstream Guards, brightly coloured, standing proud, super shiny, impressive soldiers.

Now think of those fish in the same vein, and you shouldn’t go too far wrong. In fact, if you can detect any blood present on the fish that is the same colour as our HMCG’s coats, you should be about spot on for great fish.

If the fish you are looking at has its head on and belly intact (round, whole) the eyes should be clear and glossy, the bellies should be firm. The eyes should not be discoloured or sunken. The bellies should not be soft or split (although wild Sea Bass bellies usually are a little soft). The shoulders and flank should be firm to the touch and immediately spring back to its natural shape. Your fishmonger’s fingers should not leave a dent on the flesh, although Hake is very much the exception to the rule which has a very soft flesh.

I am not a lover of the statement I have heard “Bright Red Gills”. The reason being, not all fish have bright red gills. Yes, a super fresh just out the water Sea Bass may have Pillar Box red gills, but an equivalent fresh Mackerel will have a deep ruby red gill. Gills should be of a colour “red”, any slime within the gill area should be clear and fresh smelling. Gills should not be light biscuit brown, sticky, stuck together or omitting odour. Do remember, that there are over 150 different species of fish sold on Billingsgate Market trading floor that your Fishmonger has to choose from. These fish may not only come from different parts of the world, they will come from different depths of water and feed on different things, so they cannot all have the same colour gills or totally the same characteristics

Fillets of fish are a bit more difficult to assess the quality, due to the obvious fact that everything but the flesh has been removed.


The shades of white will vary from species to species. Oily fish are quite dark, creamy colour so do bear this in mind. Salmon varies from pink to orange. White fish – Cod, Haddock, Plaice, etc, will have varying colour flesh from almost pure white of the Cod, through creamier of the Haddock and Pollack to shades of pink and hints of grey for Coley. There should be no brown and dry areas of a white fish fillet. The flesh should not be gapping. The above is just a guide to get you on your way with “some fish”. Do speak with your fishmonger, who should be happy to show you how wonderful his fish is.

Still worried about what is a “fresh fish”? If so, why not buy high-quality, frozen-at-sea fish or fish from a highly reputable frozen fish company. Defrosted in the correct manner and you will have a wonderful meal.

So, you have your great quality fresh fish, or your super, frozen, great quality fish, now what about condition? Is it the right time of year to eat that fish? Is it at its best, or is it in the heart of its breeding time if it’s a wild caught fish? Or has the farmer allowed the fish to mature if it’s farmed. This is another whole different article, so let’s just assume for the above article that the fish we are talking about is in season and for the most part, it’s from a sustainable wild fishery.

Still need some extra help and guidance? Then please check out the Seafood School at Billingsgate website.

Monkfish Cod Haddock Pollack