Everything you need to know about grilling fish on the BBQ

Some people shy away from grilling fish on a BBQ. Perhaps it's the unfamiliar territory, and there's something particularly daunting about it falling apart and us potentially ruining a beautiful piece of fish.

But the truth is, that learning how to grill fish on a BBQ is surprisingly easy. And the results you get from grilling fish are so much tastier than what you can achieve in your kitchen. Not to mention you won't have to deal with the strong after-smell which always spreads throughout the house, in spite of our best efforts.

But seriously, there is no reason that fish shouldn't be featuring regularly on your list of recipes to cook on your best BBQ. Learning how to cook a whole grilled fish gives you a show-stopping centrepiece, as well as being healthy dish that's packed full of flavor.

'Fish on the BBQ seems to be one of those things people shy away from, but we really shouldn’t,' says Mike Tomkins, MasterChef 2021 runner-up and brand ambassador for Thermapen. 'Cooking fish over fire is, in my opinion, the best – it releases all the smoky flavors in a delicate piece of fish or really accentuates the strong flavors in shellfish.'

Grilling fish on the BBQ in 6 easy steps

'Cooking a whole fish on the grill is absolutely the best way of grilling fish,' says Cesar Fernandez, Chef at Miele. A freshly grilled whole fish can be the pièce de résistance at a BBQ party. And when these expert fish grilling tips are followed, it will not only look incredible but the taste will be sublime. 

1. Choose your fish

'You can cook pretty much any fish on a grill,' says Sam Wanstall, head chef at Traeger Wood Pellet BBQs. But what fish you choose will dictate how best to cook it.

'Salmon and other oily fish are natural choices for the grill, as they're unlikely to dry out and readily take on delicious smoky flavors,' says Ross Bearman, Great Taste Judge and Founder of BBQ Gifting Company, Ross & Ross Gifts. 'White fish works well too, but takes even less cooking - I like to parcel mine up in tin foil with butter and herbs, then grill.'

'Some fish like mackerel you can cook direct over lump charcoal or briquettes, and you can also add some smoke chips for extra flavor,' says Jack Stein, Food Director at Rick Stein Restaurants. 'Mackerel, monkfish, sea bass – these are all solid meaty fish. Flaky fish such as cod aren't as good,' he says.

So whilst flaky fish can be cooked on an outdoor grill, you may wish to use a fish basket, or wrap in foil, to keep the fish from falling apart. 

For something a little more exotic, Cesar Fernandez likes sea bass or sea bream but 'if you can get hold of some red snapper, definitely give it a try,' he says.

'Monkfish, cod, king prawns and haddock are ideal for kebabs,' says Sophie Nahmad, Chef at Gousto 'Marinade these first, then cut into 1.5 inch cubes (except prawns which can remain whole) and thread onto skewers with your choice of vegetables. If using wooden skewers, soak these first to prevent them burning.'

2. Decide on your flavors

'If you want to keep the fish flavor nice and simple, nothing beats fresh lemons and fresh herbs,' says Cesar Fernandez. 'I quite like burnt sage that you can do over a naked flame or whilst your charcoal or gas BBQ is preheating. 

'One of my favorites is to use a good quality sambal, a spicy sauce quite common in countries such as Malaysia which packs a strong punch and works extremely well with whole fish,' he says. It will even make for a warming option for the winter BBQ.

'The quickest and easiest marinade is just two grated garlic cloves, the zest of a whole lemon, some olive oil, salt and pepper,' says Cesar. And Jack Stein recommends scoring the fish to get more flavor in and seasoning before and after cooking.

'I love to cook a fish whole over the fire, as this is minimum fuss,' says Jean Delport, Executive Chef of Restaurant Interlude. 'Load the inside of the fish with fresh soft green herbs, sliced lemon and season generously on outside of the fish, before grilling on open fire coals.' 

Once you've chosen your fish, make sure you scale, pat dry and oil both sides ready to place on your grill.

3. Fire up the grill

'An important step when grilling fish is to light a BBQ and pre-heat it on high,' says Dan Cooper Head Grill Master at Weber. 'This will help in a number of ways; first, it will caramelize the fish and provide the defined grill marks to supply that immense flavor all grillers love.

'Second, it will reduce the amount of time your fish is on the barbecue, resulting in less opportunity for your fish to dry out. Last, it will also prevent the fish from sticking – which is often a big fear for grillers! Fish sticking will make cleaning a BBQ a much tougher task.' Our tips on how to clean grill grates will come in handy if you do get fish stuck on your BBQ.

Sam Wanstall says: 'For a whole fish I would suggest a temperature of 360˚F to 430˚F (180˚C to 220˚C) depending on the recipe and what kind of fish you are cooking.'

4. Introduce that smoky grill flavor

'If you normally cook on a charcoal grill these are great for grilling fish,' says Surinder Multani Owner and BBQ Expert at BBQ Outlets. 'So when it comes to gas vs charcoal grills, you'll find that charcoal usually helps bring out better flavoring when grilling fish.'

If you don't have a charcoal grill, it could be worth learning how to use a smoker box on a gas grill if you want to achieve that intense smoky flavor. 'If you have a smoker box you'll need to add wood chips, however, you don't need to soak the wood chips,' advises Surinder.

'Grease the grill grates thoroughly before laying the fish down so that it won’t stick, or we suggest placing the fish on a greased foil sheet or even better, a wooden plank. If you plan to smoke the fish on a wood plank, soak the plank in water for at least one hour ahead,' she says.

5. Get your fish on the grill

Make sure you've scored the skin of your fish first urges Mike Tomkins: 'This one is really easily overlooked but you need to score the skin of fish before cooking. Naturally through the cooking process, the skin will tighten and shrink. If you haven’t scored the skin you’ll end up with a curled piece of fish,' says Mike. 

'You can put some fish directly on the grill, however, fish can be delicate, and if the grill isn't properly prepped/greased the fish can get stuck on, or worse, fall apart through the grates,' says Surinder Multani.

If you're nervous about this happening, do as Sam Wanstall does and use a grill basket, available from Amazon. 'For more delicate fillets, I would suggest these are placed on an accessory such as the Traeger Stainless Steel Grill basket. With the perforated holes this allows the fish to gain all the wood fired flavor as it is able to penetrate the fish all over, without the risk of it falling between the cooking grates.' 

Alternatively he suggests placing fish skin down on butcher paper as this allows the fish to cook whilst the skin sticks to the butcher paper and then can easily be disposed of.

Then there's the foil option. 'I don't personally use foil,' says Jack Stein, 'but it is a great way to steam the fish slightly and introduce marinade to the cooking process. For something a little different you can lay some fennel sticks or celery and put it on top.'

6. Cook through and serve

Dan Cooper has a simple method to calculate cooking time for grilling fish: 'Per inch of fish, the general rule of thumb is to allow 8 to 10 minutes of grill time. So, for example, if your fish is two inches in thickness, grill each side for about six to eight minutes.' 

For a foolproof way of ensuring your fish is cooked through to perfection, Mike Tomkins recommends probing the whole fish with a cooking thermometer like the Thermapen ONE.

'140˚F (60˚C) degrees is the magic number for most fish to be cooked, and it couldn’t be simpler if you’re cooking to temperature. So keep a charcoal grill hot and take fish to around the 135˚F (58˚C) mark before taking it off the heat and allowing the fish to rest for a few minutes. Like any other food, there will be some carry-over cooking, although this is dependant on the thickness of the fish.'

Dan Cooper's essential tip for grilling fish is: 'When you’re learning how to grill fish on a BBQ without the skin, make sure you only flip it once while grilling. Do not repeatedly turn and flip it as this will heighten the chance of it breaking apart while being barbecued.' 

How to grill fish on a wooden plank

Grilling fish on a wooden plank is a fantastic way of giving your fish a deep, smoky flavor, and can be particularly useful if you don't have a charcoal grill or a smoker. 

'If you plan to smoke the fish on a wood plank, soak it in water for at least one hour,' advises Surinder Multani. This is a crucial step as this is what will prevent your plank of wood from catching fire on your built in BBQ, freestanding BBQ or if you cook on a fire pit.

Once soaked put the plank on the grill over indirect heat. The plank will then heat up and make the meat smoky as it slowly cooks.

What is the best way to cook fish on a grill?

'The best way to grill any fish BBQ recipe is to get a great sear and color to start, then allow it to finish cooking gently until fully done,' says Cesar Fernandez. 'If you want to know if your fish is ready, simply keep an eye on the inside of the cavity, when the thickest part looks opaque, it’s done.'

Like with how to BBQ chicken safely, it helps if you have a meat thermometer to hand. For grilling fish just make sure it reads 140˚F (60˚C) at the thickest part and it’s done!'

'Ideally you want to keep your fish gutted, but whole, this will allow you to both get a super crispy skin and to infuse the fish with any herbs or citrus by stuffing the cavity. Make sure you grease your fish quite well before, either with a brush, or ideally with a spray oil,' says Cesar.

'Wrapping fish in foil is pretty fool-proof and cooking directly over coals is great if you want a really crispy skin, but honestly it all depends on what final dish you have in mind. An oily fish like mackerel is perfect for cooking directly over flames - this is because it’s quite an oily fish, so can withstand the direct heat of the grill. If you remove it at 135˚F (58˚C), it certainly won’t be dry,' says Mike Tomkins.

How long do you cook fish on the grill?

'This really depends on the fish, the recipe and the cooking method, says Sam Wanstall. 'But if you want to grill a whole fillet of white sea fish like sea bass, halibut or cod that would take about 15 minutes at a temperature of 320˚F (160˚C).'

With how to BBQ a turkey you allow a certain cooking time based on weight. Similarly with how to grill fish, a sure fire way to work out cooking time for any fish is to allow 8-10 minutes of grill time per inch thickness of fish.

As well as factoring in cooking time Dan Cooper recommends allowing your fish to sit for five to 10 minutes to bring it up to room temperature before grilling. Then allow adequate time for your fish to rest after it is off the barbecue. 

'Around three to five minutes is usually a sufficient amount of time to let the fish relax and allow for the juices to run back into your cut of fish, making it more tender,' says Dan.

Should you grill fish in foil?

'You don’t need to grill fish in foil – you get the best flavor from your fish being open to the smoky fuel of the BBQ', says Sam Wanstall. However you can grill fish in foil if you would like to. 

'Personally, I love cooking a whole fish wrapped in foil,' says Mike Tomkins. 'I stuff the fish with some lemon, plenty of butter and some herbs before adding a splash of white wine into my little fish foil parcel.'

'By doing this, you’re capturing all the moisture in the fish and ensuring there is no chance of your fish drying out. I set my BBQ to around 390˚F (200˚C) degrees but cook indirect and away from the coals to avoid the fish cooking unevenly,' says Mike.

Do you grill fish directly on a grill?

Cooking fish directly over coals is great if you want a really crispy skin and delicious smoky flavor. Clean and scale your fish first, Jack Stein advises, making sure it is dry before adding a tiny bit of extra virgin olive oil. Failing to oil your fish and/or grill will result in skin sticking and things will fall apart.

'Don’t touch it whilst it's cooking,' says Mike Tomkins. 'Everyone loves to move the fish around and have a look, but trust the process! Leave your fish skin side down and probe it regularly for temperature, when it reaches the right temperature you’ll have a beautiful crispy skin on your fish.'

For more delicate fillets, Sam Wanstall thinks these are better placed on an accessory such as a grill basket. This removes all worry of the fish falling apart and falling through the gaps in your grill. And with a grill basket you still get that smoky taste.

If you don't have a grill basket and if you're in doubt about the structural integrity of your fish, wrap it in foil.