What’s the Best Hook Size for Trout? It Varies, but Smaller is Usually Better

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Size 14 hooks in a pack.

The best hook size for trout is generally fairly small, particularly if you’re fishing rivers for trout that either come from behind lures or flies to eat, or for fish that rise from the bottom. Most trout food is fairly small. You want your flies or lures to resemble natural food sources.

Last winter, I was doing some very technical trout fishing on Idaho’s Silver Creek. The stream is a very famous spring creek in south-central Idaho that’s home to some seriously big rainbows and brown trout. 

The key to catching Silver Creek’s big trout is to be “spot-on” with your fly. In other words, do your very best to match a natural food source. And, make the fly “behave” naturally.

These fish are extremely educated. They also live in very clear water. They can see their food, and they can see any threats. For these experienced trout, I used a size 20 Zebra Midge fly pattern on the drift.

And, because the creek is home to a prolific winter midge hatch, I’d managed to catch a few trout. I caught one brown trout that stretched the tap to almost 22 inches. 

You may be asking yourself, “Why would such a big fish eat such a small bug?”

Well, most trout food is rather small. There are exceptions, but when fishing for trout with flies or lures, take a look at what’s on and in the water. Chances are, the bugs you see will be pretty small. 

The hook of your fly pattern should be small, too. 

What’s the Best Hook Size for Dry Flies?

Again it depends on the water and the natural prey base. Generally speaking, however, I would say that the average dry fly is tied on either size 14 or size 16 dry fly hooks. 

How big are these hooks? Not very big. And that’s because the mayflies, caddis flies, smaller stoneflies, tricos and midges aren’t very big, either. 

For small dry flies, like a Blue-winged Olive or a small midge, I’d go even smaller. Here, on my home river in eastern Idaho, my “go-to” dry fly in the fall, winter and spring is a size 20 Blue-winged Olive. 

That’s a very small dry fly. 

But, during high summer, bigger bugs are on the water. Insects like giant stoneflies or grasshoppers should be tied on bigger hooks. For the average ‘hopper, I’d go with a size 10 fly. For a big stonefly, I’d go even bigger — like a size 8. 

Now, while these hooks are, indeed, bigger, they’re still not very big. If you fish for bass, crappie or other panfish, these hooks will still feel quite small. 

What’s the Best Hook Size for a Nymph?

Again, you want your fly to resemble the bugs that are in the water. Nymphs are flies that are tied to imitate aquatic insects in their larval stages. They are fished below the surface. 

These are the bugs that “hatch” into mayflies, caddis flies and stoneflies. Often, their larval bodies are smaller than their adult bodies, but generally not by much.

For your average nymph caddis fly larva, I would tie a nymph in about size 14. For stonefly nymphs, I’d go much bigger. Consider a size 6 hook. 

What About Streamers?

This lake trout ate a size 6 streamer.
Lake trout are usually larger fish that eat other fish. Therefore, the best hook size for lake trout flies is right around size 6. This lake trout ate a size 6 streamer.

Streamers are flies that are tied to imitate bait that swims. Some good examples of streamers are Woolly Buggers, Zonkers and Muddler Minnows. The Clouser Minnow is also a good example of a streamer pattern. 

Generally, streamers are bigger flies. That means they’re tied on bigger hooks. I would estimate that the average Woolly Bugger is tied on a size 8 hook, with variations as big as size 2. 

By now, you’re likely noticing that the smaller the number of the hook size, the bigger the hook is

Streamers, particularly for big trout, can be quite big — some are as big as a size 0 or even 1/0 and 2/0. For trout, these are big flies. 

Final Thoughts

For the most part, you’re going to be better off fishing for trout with flies and lures on the small side. There are instances where you can size up, particularly if you’re fishing for bigger trout. Generally speaking, though, smaller is better for most trout-fishing scenarios. 

Dry flies and nymphs are tied to imitate specific insects, and those insects are often very small. Streamers, however, can be bigger, because they are tied to imitate larger prey items, like minnows, sculpins and leeches. It’s fine to go with bigger hooks for these larger flies. 


Do Big Trout Eat Small Insects?

Yes. All the time. Certainly, big trout will chase larger prey, but small insects, like midges and tricos, are often readily available and don’t require trout to expend energy. They can eat a dozen midges without moving much at all, or they can chase a minnow and expend serious energy, with no guarantee that they’ll actually catch it. 

What’s the Best Hook Size for Rainbow Trout?

Just like other trout, rainbow trout tend to eat whatever is available to them. I’d recommend a dry-fly hook size of size 14-16 for rainbows. 

Is a Size 4 Hook Good for Trout?

A size 4 hook would be good for larger trout that eat prey like minnows, leeches and even smaller trout. It’a a good fly for tying streamers, like Woolly Buggers and Slumpbuster. 

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