Video: how to gut, scale and fillet a fish with Darina Allen

| 19th November 2009
Darina Allen
Darina Allen

Darina Allen, Irish TV presenter and author of Forgotten Skills of Cooking

One of Ireland's best-known chefs, Darina Allen takes the fear out of buying fresh, whole fish with her simple preparation guide

Buying fresh fish

For those of us who love fish, the skill of being able to judge accurately whether fish is fresh or not is vital. The most important thing to remember when buying or sourcing fish, is that fresh fish never smells, it just has the merest scent of the sea, reminiscent of fresh seaweed. Fresh fish looks lively and stiff, and the skin glistens.

By the time the eyes are sunken the fish is a week old. Stale fish looks distinctly miserable; the gills will be dark and the skin can be gritty and dry, and it has a strong fishy smell. It doesn't matter if the fishmonger winks at you and says he caught it himself, if it smells, it's not fresh.

That's all straightforward enough, but between the time fish is really fresh and the time it is really stale there are several days during which time it will be gradually deteriorating. It is during this period that it is most difficult to tell just what condition it is in, particularly if the fish has been filleted and cut into small pieces. You have to judge by the colour and smell. Check that the flesh of white fish is white and not at all discoloured and that the under-skin of flat fish is quite white and not yellowing.

For those who live far from the sea, frozen fillets can be excellent. Good firms freeze their fish in prime condition within hours of being caught, so it is far preferable to buying ‘fresh' fish that is several days old.

First decide whether you need to scale the fish. Grey sea mullet has scales as large as a thumbnail and definitely needs scaling. Other fish with smaller scales, such as plaice or sea bream, need not necessarily be scaled. Some fish either have tiny scales or are completely smooth so don't need to be scaled at all. If you're poaching the fish, there is no need to scale the fish as the skin will be taken off after cooking. I always leave the skin on in this case as I feel the scales help to keep more flavour in. If you're pan-grilling, however, the fish must be scaled because you'll want to eat the delicious crispy skin and crispy scales are quite a different matter!

How to scale a fish
Remove the scales by holding the fish by the tail and pushing against the scales with the back of a knife from the tail to the head on both sides.

How to gut a fish
Flat fish are gutted in the boats as soon as they are caught because their insides deteriorate very quickly, so you just need to wash them out thoroughly. You can use the method below to gut any round fish, such as salmon, mackerel, pollock and grey sea mullet.

It's best to gut fish close to the sink. Put a chopping board on the drainer and cover with a couple of sheets of newspaper. If you are cooking the fish whole, you don't need to remove the head. However, if you plan to fillet the fish you may find it easier to remove the head before gutting, for ease of handling.

Lay the fish on its side, lift up the fin below the head and using a filleting knife, cut off the head. But rather than cutting straight across, cut into a V-shape around the back of the fin so you don't waste the lovely thick piece of flesh at the back of the head. Turn the fish over and repeat on the other side. Then twist the head and detach it from the body. Discard the head or use for fish stock (in which case you'll need to remove the gills first).

Insert the tip of the filleting knife into the vent at the tail end, and slit through the belly towards the head end. Then scoop out the intestines with your hand and discard. Rinse out the cavity under cold running water. Pay particular attention to the line of blood under the backbone - this can be removed using your fingertip.

In larger fish like salmon, a teaspoon with a pointed end is a great help because you can just run it along the backbone. Rinse the fish well again and refrigerate until needed. When gutting herring, you'll want to save the roe, so slit the belly carefully so as not to damage the roes. Detach the roe from the intestines and discard the latter. Rinse the roe gently, refrigerate and use as quickly as possible.

How to fillet a flat fish

Use this method for flat fish such as plaice, sole, halibut, brill or turbot. If you are going to fillet a fish with any kind of finesse, allow yourself the luxury of a sharp filleting knife with a flexible blade.

• Place the fish on a chopping board, dark skin upwards with the head towards you. With the point of the knife, cut down the centre of the fish, onto the bone, from tail to head - just left of the spine, placing the other hand flat on the fillet to steady the fish. Keeping the knife almost flat, slide the knife between the flesh and the bone.

• Use long, sweeping strokes from tail to head to gradually detach the fillet.

• Turn the fish around and slip the knife over the spine. This time cut from head to tail and remove the fillet in the same way.

• Turn the fish over and repeat the process on the other side.

• Use the well-washed bones for a fish stock.

How to fillet a round fish

Use this method for round fish such as salmon, haddock, cod, pollock, grey sea mullet or mackerel. Use a sharp filleting knife with a flexible blade.

• Put the gutted fish on a chopping board.

• First, using the point of the knife, cut around the base of the head (if it is still attached) down to the bone.

• With one hand flat on the fish to steady it, slit the skin from the head end to the tail just above the backbone, using the back fin as a guide.

• Slide the knife across the bone in long, sweeping movements - keeping the blade as flat as possible - until you reach the pin bones. Then use your thumb to press the flesh back off the bones, and tease your knife under the pin bones until they're released.

• Slide the knife down under the rib cage and detach the remaining part of the fillet.

• Turn the fish over and detach the fillet from the other side in the same way. When filleting salmon, remove the flesh all in one piece and remove the pin bones with salmon tweezers afterwards.

How to skin fish

Put the fillet of fish skin side down onto the board. Cut through the flesh down onto the skin at the tail end. Hold onto the skin at the tail end and, with the knife at a 45° angle, half push, half saw the flesh off the skin. If the knife is at the right angle there should be no waste. Use the skin in fish stock.

Seasoning fish before cooking

Sprinkling a fish with salt on both sides and leaving it for even 10 minutes before cooking improves both the flavour and texture dramatically. Even if the fish is not spanking fresh, it firms up the flesh and imbues it with flavour. This is done a lot in Japan. It's particularly worth doing with salmon.

Excerpted from Forgotten Skills of Cooking by Darina Allen (Kyle Cathie Ltd, £30). Readers can buy a copy for the special price of £25 (inc free p+p, UK mainland only) by calling 01903 828503 and quoting ref. KC FSC/EC. Or email:


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