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    Giant trevally swimming under turquoise blue water at Alphonse Island - shot by Alphonse Fishing Co™

    Fly fishing for giant trevally

    Targeting giant trevallies on the fly is not for the faint-hearted angler. They are fierce, big, aggressive, and incredibly powerful. They are also quite often completely underestimated by new anglers but are respected by new and seasoned fishermen alike. You need more than the best giant trevally flies, the best fly fishing rods, and ideal conditions to catch giant trevally – they have earned their name as ‘the gangsta’s of the flats’ for a good reason!

    Giant trevally fish have a reputation for being thugs, bullish and unforgiving. They prey on almost anything that moves. From crabs, lobsters, squid, and eels to mantis shrimps. However, their favourite prey are be the wide variety of smaller fish that populate the shallow flats. Which mainly consist of shoaling fish like mullet, bonefish, smaller trevally species like brassy trevally, and even small power lips.

    Key facts about the giant trevally

    • Giant trevally average length 85 cm
    • Giant trevally average weight 13 kg
    • Giant trevally diet Carnivore
    • Giant trevally time to maturity 3 - 4 years
    • Giant trevally average age 6 - 7 years
    • Average giant trevallies caught on a fly with us 1,450 per year
    • Giant trevally top speed 60 km/h

    The search for the giant trevally

    It’s not uncommon to hook giant trevallies while trawling for tuna, wahoo, and sailfish in the deep blue. Conversely, giant trevallies are known to be caught in depths exceeding 80 m. In contrast, for fly fishermen the most appealing way to hook a GTs is wading in knee-deep water on the flats. The varying depths GT are found in prove that they are apex predators.

    Fly fisher getting ready to fight the giant trevally on a fly with Alphonse Fishing Co™

    Best Giant Trevally Flies

    A similar approach to giant trevally fly choice can be taken as with big barracuda. The fly choice should be dictated by the area you are fishing and the bait species that inhabit that locality. Brush flies, sempers and poppers are all effective. As a general rule, lighter coloured flies should be used on the white sand e.g. tan and white, as these lighter colours are more representative of species such as mullet, small trevally and bream. Darker coloured patterns are more suitable for surf areas and coral fingers e.g. red, black, and brown, making a realistic impression of various types of reef dwellers, grouper, snapper and emperors.

    Here are 3 flies that will always be in our guides’ boxes.

    • Black Brush

      The black brush fly has probably taken down more GT fish than any other fly that we use. The combination of adding a hint of purple, red, or olive to the black brush fly also works really well. Keith often gets asked by guests: “What fly works the best?” His standard reply is: “You can use any fly you want, as long as its a black brush fly!

      available On Island
    • Olive & Red Semper

      The olive and red semper fly, like all semper patterns, have an incredible movement in the water. The thin hackles in the tail, the marabou collar, and the EP Brush head, provide this fly with incredible action in the water. These flies are irresistible to any cruising giant trevally.

      available On Island
    • Popper Fly

      Traditional popper patterns are becoming popular as they create a greater disturbance on the water. Poppers are generally fished over deeper waters, such as drifting on the skiff in the lagoons, casting into the channels, and floating on the shallow outer reef of the atolls. Be sure to have this one ready too.

      available On Island
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    Best Giant Trevally Rod Set Up

    Everything about GTs screams ‘big’. Big fight, big flies, big fish, so naturally, you need a big rod too, therefore 12 weight fly rods are used to target giant trevally. Your rod needs to be paired with a high-quality large arbour saltwater series reel with a strong, smooth drag to match. The reel should be loaded with three hundred yards of 80 lbs braid. Once hooked, these fish love to head straight for the coral or drop off into the deeper water, which often results in a lost fish. Having a good fishing rod that you can pull very hard is necessary, therefore, any rod with a strong butt section is recommended.
    Wading for giant trevally with professional fly fishing guides at Alphonse Fishing Co™

    Best Tides For Giant Trevally

    Pushing tides are considered to be the best time to target a GT. The fish know that they have plenty of water pushing behind them on the flats and are more at ease to avoid getting trapped, as opposed to a dropping tide. As the cool freshwater flows onto the shallow flats, many invertebrates such as crab, shrimp, and worms leave their holes. This, in turn, brings bonefish and other small fish onto the flats to feed, and the chain continues up to the bigger predatory fish like the giant trevally.


    Once you spot a giant trevally, it is crucial to remain calm and listen to your guide. Move into position quickly, trying not to make too much noise and keeping your fly line clear of any potential snags. Under the guide’s instruction, make the cast. Generally, leading the fish by three to four rod lengths is good. If the fly lands on the head or behind the GT, the chances of the fish eating it are almost none. Once the fly is presented, a long and fast retrieve is necessary. Once the fish eats the fly, keep the rod tip pointing down, and set the hook by strip/line setting. Lifting the rod in an attempt to set the hook is not effective and gets the hairs on the back of your guide’s neck to stand on end. Only once the giant trevally is on the reel can you lift the rod and fight. And to be clear , you need to get ready for one hell of a fight!

    Photos of giant trevally caught on a fly

    Explore our latest photos of the giant trevallies caught here. Some of the big GTs that did not get away.
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    "This was my dream catch, she was huge and put up a heck of a fight." - Craig Williams

    Tips to catch the giant trevally on a fly READ MORE

    The ultimate saltwater fly fishing destinations

    We choose destinations that meet our fly fishers’ needs and desires. You can focus on one atoll or combine several for a richer and more varied experience.
    • Alphonse Atoll

      Alphonse Atoll

      Two atolls and islands called Alphonse, Bijoutier and St Francois.

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    • Cosmoledo Atoll

      Cosmoledo Atoll

      One atoll with a vast lagoon surrounded by nineteen islands.

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    • Astove Atoll

      Astove Atoll

      One atoll with an enclosed lagoon surrounded by flats and sheer drop offs.

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    • Farquhar Atoll

      Farquhar Atoll

      One atoll with a vast lagoon surrounded by nine islands.

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    • Amirante Islands

      Amirante Islands

      African Banks, Remire Reef, St Joseph’s Atoll and Poivre Atoll.

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    • Providence Atoll

      Providence Atoll

      One vast atoll with a shallow lagoon, sand banks, flats and channels.

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    Turn your fly into a fish’s ultimate temptation. Seychelles, with its 115 islands and deserted atolls, ideal weather and warm Indian Ocean waters, is renowned for being home to some of the world’s richest fishing grounds. You don’t even have to venture too far to break fishing records!

    Happy man, enjoying his moment with the flats caught giant trevally (caught on the fly at Cosmoledo) during his holiday with Alphonse Fishing Co™
    Unique experiences like nowhere else

    Our Fly Fishing Highlights

    • Home of the world's best fly fishing
    • Unique, bespoke trips to suit your needs
    • Located in the pristine remote outer islands of the Seychelles
    • Luxury accommodation and exquisite food
    • Unrivalled professional guides
    • Some of the richest fishing grounds in the world
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    Let us craft the ultimate giant trevally fly fishing experiences for you Enquire Now