Fishing Flies: Getting a Hook On It

I’ve been teaching a friend’s son how to tie fly fishing flies, and he came up with an interesting question.

“How come,” he asked, “a streamer hook, which is three times the size, carries the same number as a regular hook?”

Well, I explained, the streamer isn’t really three times the size of the other one. It’s just longer.

Hook sizes for fishing flies are determined by the width of the gap between the point and the shank. If you hold a #10 streamer hook and a #10 bait hook together, that gap will be the same, even though the two hooks are otherwise dissimilar.

Those dissimilarities are based on the configuration of the hook, not it’s basic size. For instance, there is an industry standard determining the length of the shank as compared to the gap. That would be for a regular hook. Streamer hooks have shanks that are 3x or 4x the standard length. The box should identify them that way, saying something like “#10, 3x hook.” Some such hooks are as much as 6x long. But if you lay the ends together they’ll still be the same size.

By the way, hook sizes for fishing flies run in descending order. That is, the larger the number, the smaller the hook. In theory there is no limit to how small a hook can be made. In practice, #28 is the smallest commonly available, but they do make them as tiny as #32s.

Any hook larger than #0 goes the opposite way, using a two-digit system with the numbers separated by a slash. The next largest size after #0, for instance, is #1/0.

The diameter of the wire used to make the hook also creates the appearance of different sizes. As with shank length, there is a standard sized wire for each hook size. But the same design also can be available in thin wire, or extra thick wire, depending on end use. Forged hooks are always thicker than standard. And gold hooks appear to be thinner, even when they’re not.

Another aspect to consider when tying fishing flies is the shape of the bend, because they affect how the hook is perceived (as well as theoretical hooking power). Some hooks have bends that are perfectly round. Others sort of taper, as if somebody squeezed the bend in a pair of pliers. And others, the so called circle hooks, have the shank continue the curvature of the bend, making them appear to be a different size. Many of these styles actually have names, but I don’t know a single fishermen who’s ever used them.

What you do have to know is the relative size of hooks. If you’re fishing bluegill with a #10 bait hook, and somebody says the hook is too big, then you know to change to a #12. But other than that, fly fishermen are the only ones to whom size matters as a regular thing. But that’s because there are trying to match artificial fishing flies to the size of natural ones, which also are identified using the same size designations.