Fly Fishing For Rainbow Trout in the UK: Top Tips

Female angler fly fishing for Rainbow Trout in Scotland

Rainbow Trout are distinctive, thanks to their silver bodies and streaks of purple, pink and blue, making them a sought after fish for fly fishing anglers across the UK.

As one of the most popular species to fish in the UK, we’ll take a look at everything you need to know about fly fishing for Rainbow Trout, including where and when to go to land a catch, the best tackle you should use, and our top Rainbow Trout fishing tips.

What are Rainbow Trout?

Despite being one of the most popular species to fish in British waters, Rainbow Trout aren’t actually native to the UK.

It’s native to the cold-water tributaries of the Pacific Ocean in Asia and North America, and was introduced to the UK in the early 20th century. It was first introduced to fish farms, and is now established in rivers and lakes across the country.

Rainbow Trout can live in water that’s of a poorer quality than brown trout, the only trout species that’s native to the UK.

This type of trout is a predatory species, which feast on insect larvae, small fish and flying insects like mayflies and damselflies. They’re one of the strongest fighters among trout, meaning that it can be a battle to land a catch – but one that is ultimately thrilling when you manage to win the fight.

What is the difference between Brown Trout and Rainbow Trout?

Rainbow Trout and native Brown Trout look fairly similar, but it shouldn’t be hard to spot a Rainbow Trout thanks to its streaks of colour.

The easiest way to tell the two fish apart is their colouring. Brown Trout are, unsurprisingly, brown in colour, with reddish spots along their body. They have a yellow or orange belly.

Rainbow Trout are silvery-brown in colour and have spots from head to tail, as well as streaks of purple, red, blue and pink along their flanks. They also have a white belly. They’re also sometimes known as ‘red band trout’ due to these streaks of colour.

As well as their colouring, you can usually tell the difference by their size. Brown Trout tend to grow longer and heavier than their Rainbow counterparts.

Brown Trout are usually between 15 and 22 inches in length, and weigh between 0.5 and 2.5kg (1-5 pounds), although they can be as heavy as 9kg (20 pounds). Rainbow Trout, on the other hand, are most commonly between 12 and 20 inches, and tend to weigh between 0.5 and 2kg (1-4 pounds).

A freshly caught Rainbow Trout.

Fly fishing for Rainbow Trout in Scotland

Rainbow Trout aren’t indigenous to Scotland and don’t breed in the waters, meaning that all of the Rainbow Trout in the country are reared either for sport or for food.

Although not a native species, Rainbow Trout can be found across the country and those reared for sport have been introduced to managed lakes and reservoirs to provide fantastic sport fishing.

Rainbow Trout fishing in Scotland can be enjoyed either from boats or from the bank, and it can be done all year round. Find out more about fly fishing in Scotland with LOOP Travel and start planning your fishing adventure to some of the country’s most scenic spots.

What time of year should you fish for Rainbow Trout?

You can go fly fishing for Rainbow Trout at any time of year, but you’ll usually have the best chance of landing a catch in spring when the water starts to warm up.

Rainbow Trout spawn between March and June depending on the water they’re in. Their preferred temperature for spawning is 4.5 to 10°C (40 to 55°F), so you may want to take a temperature gauge with you to help determine how active the fish will be in the river or lake you’re targeting.

Late Summer to Autumn are some of the best times to target Rainbow Trout as they’re feeding in preparation for the winter months. During the height of the summer months, fish may head for deeper water, but there are still plenty of opportunities to target them in the warmer months, so any time from July/August onwards is recommended.

It’s best to fish for Rainbow Trout during the morning and evening. That’s because hatches occur during these time periods and the fish are most likely to be feeding. Rainbow Trout aren’t as active when it’s warmest, during the middle of the day, so you’re less likely to catch any during this time.

What equipment/tackle do you need to fly fish for Rainbow Trout?

To be in with the best shot of catching Rainbow Trout, there are a few specific pieces of fly fishing equipment you should consider taking with you.

Best rods for fishing for Rainbow Trout

The best fishing rod for Rainbow Trout depends on where you’ll be fishing.

If you’re planning to visit mountain streams and small rivers, a 3- or 4-weight single handed rod is the best choice. Lightweight and easy to use whether you’re a beginner or experienced angler, these rods will give you control and accuracy for the smaller Rainbow Trout you’ll find in these environments.

If you’re fishing in medium to large rivers, you’ll need a heavier-duty rod that can handle the bigger fish in these waters. Here, you’ll be better off using a 5- or 6-weight rod.

Male angler fly fishing for rainbow trout with a LOOP fishing rod

Best clothes for fishing for Rainbow Trout

If you’re targeting Rainbow Trout in Scotland, it’s best to keep in mind that the weather can be unpredictable – even during the summer months. It’s a good idea to wear plenty of layers that you can add or remove depending on the weather conditions.

A good fishing sweater, either a hoodie or zip up top, is an essential. Wear it on its own on milder days, or layer under a jacket to keep you warm in cooler weather. Look out for materials that offer increased warmth and durability, and added features like thumb holes and pockets.

A good-quality jacket is another essential to ensure that a spot of rain doesn’t put a damper on your fishing plans. Choose a jacket made with technical fabrics to keep the wind and rain out, and a storm hood to offer extra protection in even the harshest weather conditions.

Best flies for fishing for Rainbow Trout

The Griffith Gnat Fly is undoubtedly one of the best flies for Rainbow Trout fishing. Midges or gnats make up the basis of the trout’s diet, with these tiny insects being found on most rivers, lakes and streams around the world.

The Griffiths Gnat Fly imitates the egg-laying adult midges and emerging midges, meaning Rainbow Trout are unable to resist.

This is a fairly universal fly that you’re likely to have success with wherever you’re fishing, but some other options include:

  • Elk Hair Caddis, which imitates stoneflies and caddis flies, and works well during hatching.
  • Parachute Adams, which imitates mayflies and caddis flies and works best in spring and autumn.

5 top tips for Rainbow Trout fly fishing

You’ve got the right clothes and the best tackle. Now, here are our top tips for how to fish Rainbow Trout in a lake, river or stream.

1. Match your surroundings

It’s best to try to camouflage your clothing and make yourself as inconspicuous as possible when fly fishing for Rainbow Trout.

You’ll be in the water or very close to the bank, so unless you blend in with the environment, it’ll be very easy for the fish to spot you.

Dress in neutral colours and avoid anything overly bright that will make you stand out against the blue water, grey river banks or against the sky.

And it’s not only your clothing you should think about. Remember to move quietly and speak softly so as not to alert the fish to your presence.

2. Watch the water

The Griffiths Gnat Fly is a great choice for Rainbow Trout, but it’s important not to rely on it. If you’re not getting any success, it could be that it’s not the right choice of fly for that particular day and location.

Be sure to watch the water to analyse the feeding habits of the trout. That way, you can determine what fly is best to use for a better chance of success.

3. Make sure you’re carrying alternate flies

That means it’s important to carry a selection of flies in a fly box, so you have the option to try new things if they decide not to feast on your chosen fly.

Rainbow Trout respond well to a variety of different flies, so just because they’re not tempted by one doesn’t mean that your day is doomed. They may be more interested in certain flies depending on the time of year. It’s always best to carry a selection so you can try different ones depending on the time of year and location.

4. Try going under the surface

Rainbow Trout tend to hunt beneath the surface, often finding leftovers or vulnerable larvae. Instead of waiting for Rainbow Trout to come to the surface, try using wet flies, streamers and nymphs to present the pattern to the fish.

5. Take a break

There’s nothing worse than stopping for lunch just as the trout become more active in the water. But you are going to need to take a break at some point during the day. So be sure to check the local hatch times before your trip to the bank to ensure you can plan your day and have the best chance of success.

Rainbow Trout are popular for beginner and experienced anglers alike, thanks to their abundance in streams, rivers and lakes around the UK, and their willingness to respond to a variety of different flies.

You’ll have the best chance of success when it comes to fly fishing for Rainbow Trout if you bring a choice of flies, dress appropriately for the weather (especially if you’re fishing in Scotland), and plan your day well.

Check out more tips and tricks for fly fishing at the LOOP Akademi, including everything you need to know about fly fishing for beginners, or if you’re looking for more tips for UK fly fishing, learn how to fly fish for salmon.