Melanie Leyshon is the editor of Healthy Food Guide magazine. She's a flexitarian and couldn’t get through the week without yogurt and yoga.

Filleting a whole fresh fish is a tricky job best left to the experts, I’ve always thought. For me, that’s Mr Moxon at the fishmonger’s in London’s East Dulwich. He’s not cheap, but he sells sushi-quality salmon and tuna and the freshest whole fish, which he prepares with razor-sharp incisions without any fuss.

I’m happy to pay for his filleting expertise and for the fact he’s out buying the freshest catch from 2am most days. But I’d eat a lot more of his quality fish if it was more affordable. A healthy diet should include two portions of fish a week, with one being oil-rich, so it’s an issue.

DIY filleting

The only way to buy cut-price quality fish is to cut out the middleman. That means heading to a commercial fish market. Anyone can shop at my nearest, Billingsgate in east London (it’s the UK’s biggest inland fish market). You can buy a freshly caught farmed 400–600g sea bass for a bargain £5.50. This gives you two thick, meaty fillets that put some pre-packed supermarket fish to shame.

What you need to know

* Get there early Billingsgate Market is open daily from 4am to 9.30am, Tues to Sat. The busiest day for the public is Saturday.
* Look for fish that really doesn’t smell of fish but has a fresh saltwater aroma (old fish will smell of seaweed). Eyes should be flat and clear, not sunken and dull; scales smooth, not dry and broken; gills a deep bright pink.
* Learn how to fillet a fish at a class. CJ Jackson, CE0 and tutor at Billingsgate Seafood School took us through the process and by the end of the class we all tucked into our perfectly trimmed fillets with salad (see recipe, below). Find a course at or call 020 7517 3548.
* For filleting at home you will need: a pair of sharp scissors, an exceedingly sharp flat-bladed knife, a damp j-cloth to hold the fish in place, a plastic chopping board and a fish descaler.

Here’s a healthy supper to try…

Grilled sea bass with fennel, rocket & orange salad

Prep: 15 min + chilling
Cook: 6 min
Serves: 2

2 x 170g seabass fillets
Cooking spray oil
Freshly chopped rosemary leaves

For the salad
½ bulb fennel, very finely shredded
50g rocket
Pared zest ½ orange, cut into thin strips and blanched
1 orange, segmented

For the dressing
2 tbsp sunflower oil
1 tbsp walnut oil
Lemon juice, to taste
A pinch of mustard powder
½ tsp runny honey

1. First make the salad: put the fennel into a bowl of iced water to crisp up for 30 min, then drain well. Toss with the rocket, orange zest and segments.
2. Whisk all the dressing ingredients together and season with black pepper. Lightly toss with the salad.
3. Preheat a grill to high and line the grill pan with foil. Put the fish, skin side up, on the foil, then spray with oil and scatter over the rosemary. Cook for 4-6 min on the second highest rung of the grill.
4. Serve the fish with the dressed salad.

Per serving
17.5g protein
10.8g fat
1.3g saturates
4.2g carbs
4.1g sugar
1.6g fibre
0.2g salt
160mg calcium
2.2mg iron