Mackerel background

Our recommendations for swaps for the UK's top five consumed fish and why you should make the swap.

Did you know that 80% of the seafood we eat in the UK is made up just five different species? We call them the big five; cod, haddock, salmon, tuna and prawns.

Not only is that really boring, but it's a pretty bad idea. It puts a lot of pressure on a handful of wild stocks and creates demand that drives unsustainable fishing and farming practices.

Take a look at what swaps you could make below and visit our Good Fish Guide to see how sustainable the seafood on your plate is.


UK stocks are doing very badly, but stocks from Iceland are healthy and are currently at sustainable levels

A sustainable swap: hake

Thanks to good management and beneficial environmental conditions hake is now a great sustainable choice.

European hake has a very similar texture to cod, with a meaty flaky texture. Swapping is as simple as substituting same weight/quantity in almost all recipes.

Cod swap


There are lots of different types of tuna, and sustainability depends on species, location and fishing methods.

Generally, the best options are skipjack and albacore caught with pole and line or handline, but make sure you check the Good Fish Guide if you are going to eat tuna as some species are red rated!

A sustainable swap: mackerel

Handline-caught from the southwest of England is the the Good Fish Guide's Best Choice. It’s caught closer to home, stocks are thriving and it’s a really versatile fish available year-round.

Mackerel is classed as an oily fish meaning it’s packed full of omega-3’s and nutrients.

If you don’t fancy whole mackerel fresh from the fish counter, then try smoked mackerel or tinned is just as good!

Tuna swap


Sourced from all over the world, prawns can be sustainable, depending on what species they are, and where and how they were caught or farmed – check the Good Fish Guide.

Generally, prawns with an eco-label like Organic, MSC or ASC are the best choice.

A sustainable swap: mussels

Give warm-water king and tiger prawns a rest. Choose UK rope-grown mussels instead, they’re one of the most ocean-friendly choices you can make.

Grown using low-impact methods, harvested by hand and get all the food they need from the sea around them. They cook in no time, and are packed full of protein and nutrients. What’s not to love?

Prawns swap


Wild Atlantic salmon is not doing so well, and the environmental performance of most farmed salmon still needs improving. In the UK, organic and Scottish ASC-certified farmed salmon is a better choice.

A sustainable swap: farmed trout

Closely related to salmon, farmed trout is a great alternative. Look for rainbow trout farmed in freshwater ponds in the UK for the best options.

Trout has a very similar texture to salmon, with a slightly stronger flavour (it’s even more delicious in our opinion!). It’s really widely available in supermarkets and easy to swap fillet for fillet in a recipe.

Salmon swap


Actually, some haddock is sustainable! Haddock from the North Sea, as well as Iceland, is currently a great choice. But why not try something different…

Why not try Dover sole instead of haddock

Why not try Dover sole from the western English Channel, where stocks are booming. Dover sole is a flat fish with a light, flaky texture and a mild flavour. It's delicious pan fried with a simple herb butter.

Haddock swap

We should all try to diversify the seafood in our diets. By mixing up your meals, you’ll help remove some of the strain placed on a handful of farms and fisheries, you'll be supporting more UK suppliers and, who knows, you might discover a new favourite fish.

Health recommendations

The NHS recommends eating two portions of fish per week, but there are guidelines on the amount of certain fish that babies, children and pregnant or breastfeeding women should be consuming. See for more info.

The seafood advice on this page is correct as of October 2021.

Is the fish on your plate red-rated?

Search our Good Fish Guide ratings and find out now