Dry Flies

Black Gnat Trout Dry Fly – New Zealand Version

Black Gnat Trout Dry Fly as tied by Keith Draper and Hugh McDowell

By Allan Burgess

The Black Gnat pattern suggests a blowfly, a common insect all over New Zealand during the warmer months of the year. Anyone who has ever cut open the stomach of a trout will know that blowflies frequently form at least part of their diet. I must admit that the sight of recently devoured fat blowflies is a little off-putting. However, it does indicate that having a few imitations of this insect are a worthwhile addition to your fly box.

Hook: 10-18

Thread: Black 

Tail: Black cock hackle fibres.

Body: Black wool, black ostrich herl, or dubbed black fur. 

Wings: Paired slips of grey mallard primary feather or starling hackles.

Hackle: Dyed or natural black cock feather.

Tied in the smaller sizes the Black Gnat also makes a good grass fly typically found in our high country streams and lakes.

As is the case with virtually all trout flies nowadays there are some good variations to be had such as this Deadly Stealth version available from Flyshop.co.nz. It incorporates black foam over the top of the body to ensure that it will be forever unsinkable.

The Black Gnat (pronounced nat) tied with a slimmer body can pass as a mayfly,  Dun or Twilight Beauty, according to Keith Draper in New Zealand Trout Flies Traditional & Modern.

A quick look on YouTube will show that there are all manner of Black Gnat variations including a sinking wet fly version tied slimmer with a mallard wing. It can also be adapted to be fished as a nymph tumbling down a stream like a drowned blowfly.

How to Tie the Black Gnat

However, I prefer Keith Draper’s dry fly version. Begin with the usual under-binding of the hook, then tie in paired slips of grey mallard primary feather. This is the fiddly part for sure especially in the smaller sizes. Secure the wings with half a dozen figure-eight wraps.

Next, work your thread to the rear of the hook and tie in a few back hackle whisks the same as you’ll use for the hackle collar at the end. 

Then comes the body material of dyed black ostrich herl. Tie in at the rear, wind the thread to the front of the hook, wrap the ostrich hurl down to the wings and tie off. Finally, tie in a black cock hackle, tie-off and cement. 

Just to add one more variation Hugh McDowell mentions using black dubbed fur for the body of his Black Gnat dry fly in New Zealand Fly Tying – The ten-thumbed beginner’s guide

McDowell also includes a wet fly version of his Black Gnat. It is the same tie as his dry fly only he changes out the upright wings for which he uses either mallard, starling or blackbird primary wing feathers (tied in as shown in the picture above) with a slip of starling or blackbird primary wing feather tied in and sloping back at 45 degrees.

The Black Gnat is a “trout fly” for every purpose. It works well on streams and still waters too, and as Hugh McDowell points out, its dark silhouette makes it a good choice for discoloured water conditions.

If tying wings on your flies looks a bit fiddly take a look at Learn Your Wings with John Hey.

This post was last modified on 25/07/2023 3:02 pm

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