a brown trout caught on a size 14 hook

The Best Hook Size for Trout (Catch More: Size Matters)

The hook size or fly size is a great conversation to have and a very interesting one at that. What size fly to fish and why is important to know. This can mean the difference between a good day and a great day on the water.

Before we discuss this any further, I can only comment on what I fish for on my waters and for the size fish I target. Obviously, if you fish for larger fish, then you will fish bigger patterns and smaller fish the same.

If I had to pick one size hook, I’d select the hook size I always start out with, which is a size 14. But like everything in life, there’s always more to the story.

River Memories

One thing that is worth remembering is that big fish eat small flies, now, I’m not saying they only eat small flies, but they do at times. I have taken some lucky shots at big trout, thinking that they may not even see a small size #16 caddis, and you can’t believe how those fish move over to eat that tiny fly.

The best hook size would be dependent on where you fish and the size of fish you fish for. A tiny spring creek that holds a small number of wild trout that don’t get much bigger than your palm would see a size #16 as the largest pattern you would tie on. While a larger stream with some larger trout would see a size #14 is the average size used. It’s all very circumstantial.

A nice brook trout caught with a 4 weight fly rod
A nice brook trout caught with a 4 weight fly rod

If I were to give an average size for trout hooks for fly fishing, I would say a size #14 would probably be the call, but again, it all depends. For bait, the hooks would be a little bigger to hold the bait, so a size #12 or #10 most probably.

Then lastly, for lures, it will depend on the lure or spinner you are casting. The actual lure is classed in numerical sizing or weight. best for trout would be a size 2” lure or anything between 1/32oz up to 1/4oz, depending on fish size.

Does Hook Size Matter for Trout Fishing?

Anatomy of a fly fishing hook
Anatomy of a fly fishing hook

The importance of hook size varies on the technique used to catch trout.

When you are euro nymphing, size is very important and not just for weight to get down but for the presentation of the pattern. A larger pattern may just be flat-out ignored based don’t the size being wrong.

When we are fishing a dry fly, the trout are a little more forgiving when it comes to the size of the dry. A size up or a size down may only make a difference on the pickier fish, but in general, if the dry is slightly too big, they will eat and vice versa.

Streamer fishing is where the boundaries can be blurred even more. When we fish streamers, we are teasing out the aggressive side of the fish and hoping to entice its predatory instincts. Fish eat with intent and very instinctively, and whether the pattern and hook are a size #6 or a size #10, the fish will most probably commit to it.

Can You Catch Big Trout on Tiny Hooks?

Catching big fish on tiny hooks is very possible and something that is mastered over time. There are a few things that assist in making this easier.

Things like your rod’s speed or how soft the tip is, your reel and its drag system, and lastly, which is the most important, your tipper strength. These three factors will greatly enhance your ability to catch large trout on small hooks.

A nice brown trout caught on a size 20 midge
A nice brown trout caught on a size 20 midge

A second factor to consider is the actual hook brand and quality. A poorly made hook won’t hold up to the task and keep on breaking. A good quality hook from a reputable brand is always the best bet. If you don’t tie your own files and buy them, then be sure to ask the local fly shop what hook size they tie their patterns on as well.

Popular Dry Fly Hook Sizes

The size of dry fly you choose to use and fish all depends on where you are fishing and what the size of the fish is (you aren’t going to throw a size #12 dry to small fish).

On my waters, I tend to fish a size #16 dry fly for most of the time, scaling up to a size #14 if I choose to fish a dropper rig. I find that size #14 dry holds a 2.5mm tungsten bead just fine, and size #16 holds a 2mm just as well. Matching the hatch is crucial here, and this will dictate what size to fish.

Dry flies, in general, have a range of sizes, starting out as big as a size #8 for the terrestrial and going down to a small size #22. They go smaller, but I can’t fish them that small, I can’t even tie them on with my poor eyesight, so I don’t bother.

Hook size comparison chart
Hook size comparison chart

My First Pick for Nymph Fly Sizes

Nymph sizes are more specific. They do range up and down like any other patterns, but we generally stick to a certain parameter of hook sizes. Sizes ranging from size #20 up to size #12 will fit most applications. I tie most of my nymphs on size #16 and scale up and down to size #14 and #18, respectively.

Bright green caddis nymph and a matching fly
Bright green caddis nymph and a matching size 18 fly

I don’t need much else and cover all my scenarios with these. Before changing or tying on a different size hook, I usually change the bead weight and then the style of the hook, i.e., a jig hook. These alternatives and variants often make all the difference.

Streamer Sizes

Streamers are meant to be big and flashy. They are meant to imitate bait fish in the waters and any other possible food source. They also scare the small fish at times, and that is exactly why we throw them for the bigger fish. The smaller trout can’t or won’t eat it.

I also carry a small streamer box that I do use for the smaller waters; most of the patterns are small woolly buggers and slump busters that I tie on jig hooks and fish in deeper pools and runs. They work wonders on those tricky trout.

Fly Fishing with Muddler Minnow
Fly Fishing with a size 6 Muddler Minnow

My normal streamer box is filled with patterns tied on size #6 hooks and upwards. The baitfish hook selection has developed over the years, and we are now fortunate to have hooks specially developed for baitfish patterns. When tied correctly, the hook will ride straight and keel correctly on the retrieve.

Another important thing to remember when choosing our streamer hooks is the GAPE size. You want a gape that won’t be covered or obstructed by the materials. Hooks like the Ahrex TP605 and the TP610 are great examples of this.

Fly Box for Big Streamers
Fly Box for Big Streamers

How Do I Match the Hatch with the Hook Size?

Important to note here is that you don’t want to be trying to match the hatch to the hook size specifically. You want to match the hatch in color and the general size of the insect. It is advisable to cover a few smaller and a few larger patterns on both sides of what the general size is.

It is a great tip to change to a smaller pattern if your dry is getting constant refusals. Change to a smaller size and fish the drift again, and you should get the eat.

A Basic Sizing Guide

Size of TroutRecommended Hook Size
4 to 10 inches (10cm to 25cm)Size #16 -Size #14
8 to 16 inches (20cm to 38cm)Size #16-Size #14
16 to 20 inches (28cm to 50cm)Size #16-Size #12
Over 20 inches (+ 50cm)Size #16-Size #10


When to Change Hook Size

Constantly being refused- When a trout is rising to the fly but not committing to the eat after a few consecutive drifts. I change the fly. Now, I don’t change the pattern at first, I first scale the pattern down by a size. So, a size #14 goes to a size #16. I rest the drift for a few minutes and try again. 75% of the time, the trout will rise and eat.

Trout missing the fly- when you keep getting eaten on the surface but for some reason keep missing the fish. One of the issues is that the hook is too big.

Guide Pro Tip: If the Trout Flat-Out Ignore Your Offering It’s Time To Change. If you are lucky enough to see feeding fish and experience a flat-out ignore of the pattern, this could be the size. The first thing to do is possibly change the color slightly and go down a size in the hook. Keep on trying these changes until you get the eat or the fish spooks.

Frequently Asked Questions About Hooks

When to use Barbless Hooks

I am an advocate for barbless hooks and only fish and tie on them. There is always a heated discussion about the topic, and I believe it serves well for the fish and fishery. No ripped jaws or bleeding fish, and the survival rate of the release trout is almost guaranteed.

How to Sharpen a Hook

Keeping the hook sharp is important. You can use those little gully hook sharpeners to keep the hook point as sharp as possible. Alternately I change the fly to the new, shaper one, keeping the pattern the same. I generally tie my flies in numbers of three or more, depending on the pattern. A great old YouTube guide is 👉 https://youtu.be/zjG0vVfd2e4

Best Fly Tying Hook Sizes

The best hook sizes to tie your flies on will vary from pattern to pattern and from area to area. A caddis nymph used here may be too small on a different river system. I’ve got a complete guide to fly tying hooks 👈 link to article.

Generally speaking:

  • Dry flies on size #20- size #10
  • Nymphs on size #20- size #12
  • Streamers on hooks form a size #10 upwards.

This is a very subjective guide and can be changed anyhow.

Looking to Learn the Tips and Techniques for the Fish You Love to Chase? I’ve Got You Hooked Up Below

One Last Cast

So, there we have it. Hook size is important to consider and use to make the right choices on the water. Make sure you have a few different sizes of the same pattern and change up and down if you are confident in the pattern.

Fish what works for you.

Tight Lines.

Kyle Knight writer Guide Recommended

Kyle Knight

Fly fishing has been my passion and pursuit for the past 20 years. I am a South African based fly fisherman who loves nothing more than spending a day on the water. Fly fishing is more than catching fish, being in the outdoors with good friends and family is what it is all about.

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