Oily fish

Although they're often overlooked in favor of more "fashionable" white fish, oily fish are a fantastic source of protein and vitamins; they are also high in unsaturated fats which makes them a healthy option, too.

In this article

Preparing oil-rich fish Cleaning Filleting

Boning Herring Mackerel

Sardines Other oil-rich fish

1. One of the first things you need to do is get rid of the gills, so lay the fish on its back and ease open the gill flaps. Ease out the fan of the gills from between the gill flaps, sever and discard.
2. Use scissors to trim off all the fins.
3. Cut open the belly of fish and take out the guts. Use cold running water to rinse thoroughly, both inside and out.

1. Begin cutting from just behind the head. Take your knife and cut into the back of the fish. Slide the knife along one side of the backbone to loosen the fillet. Try to keep the knife as close to the backbone as possible.
2. Carry on slicing along the length of the fish, cutting the fillet just after the gills and at the tail.
3. Cut the second fillet from the opposite side of the fish, using the same method as for flat fish.

1. Cut through just behind the gills without severing the head completely. Ease the head away from the body, so that most of the guts come with it. Scoop out any remaining guts using a knife.
2. Slice along the back of the fish, easing your knife between the flesh and the backbone, being careful to keep the knife pressed against the backbone, and avoiding puncturing the belly. Lay the fish out flat, opening it like a book.
3. Lay the fish flesh-side down and remove the backbone and small adjoining bones.

The tasty herring is rich in protein and vitamins. Herring has suffered from the effects of over-fishing and is less less commonly found than it once was. It is available all year but best from spring to autumn. The fish are usually sold whole. Ensure freshness by choosing large, firm and slippery fish. Clean before cooking. It's usual to dispose of the head, and the bones are soft and easily removed. Cook by boning, opening fillets out, seasoning with oatmeal and shallow-frying in butter - serve hot or cold. Herring is perhaps best cooked in white wine or light vinegar - the acid flavours suit the rich flesh. Also good scored, brushed with butter and grilled. The traditional accompaniment is mustard, though horseradish is good too. Herring can be pickled, soused, marinated, salted and smoked. Herring roe is also full of flavour and worth keeping.

Mackerel's pink, firm flesh is tasty, nutritious and inexpensive. It has distinctive silver-blue skin with dark bands and a pale belly. The skin should shine - if it doesn't, don't buy it. Available all year but best in late spring and early summer. Usually sold whole. Buy one mackerel per person for a main course. Generally choose smaller fish. Cook with or without head (the head is too oily for fish stock or soup). Mackerel is good grilled, dry-fried, barbecued or poached in white wine. Stuffed mackerel is also a popular option. The traditional accompaniment is green gooseberry sauce, though strong flavours like mustard, horseradish and curry are also good. Also suits being pickled, soused and marinated, salted and home-smoked. Ideally the skin should be crisp and a rich-brown when cooked.

Sardines - baby pilchards - are fantastic when served very fresh. These long, thin, silver fish are best when cooked near where they're caught - they don't travel well. They're available throughout winter and are best in spring, and are usually sold as whole fish. Servings of fish per person depends on the sardines since they vary in size. They're also available frozen, and the best ones are Portuguese. Remove the scales by brushing tail to head with finger and thumb under running water. Grill the sardines or barbecue them after coating with olive oil and salt. Eat hot or cold, or shallow fry after a thin coating of flour. Squeeze lemon over cooked fish and serve with crusty bread and tomato salad.

Pilchards - the adult sardine - are blue-green fish about the size of a herring. Best eaten from the summer catch, they're delicious fresh, grilled like sardines. However, most pilchards are processed and canned. Pilchards are a speciality in Cornwall where they swim to their northern limit.

Other oil-rich fish include anchovy, bluefish, horse mackerel (scad), smelt, sprat and whitebait. Fresh anchovies are best prepared and eaten similarly to sardines - they also don't travel well so are best in the Mediterranean. Sprats are tiny, silver fish with very oily flesh and are best grilled. Whitebait are young herrings or sprats and are delicious. They're quite small so serve whole - dip in milk, shake in a bag with flour and deep fry until golden brown. Serve with lemon and brown bread and butter. Smelt - from the salmon family - are good, especially when very fresh, but do go through good and bad years. Best in winter and spring. Treat horse mackerel as you would normal mackerel, though it's more coarse and bony and may not respond as well to cooking. Bluefish is available along the east coast of America and in the Mediterranean. A larger fish than other oil-rich fish, its oily, soft flesh is best with piquant flavours, and is good grilled or poached in white wine.