DEFINITION: nymph imitations with a body length less than 5mm. This means hooks size 22 and smaller. Above: little olive, tied on a hook size 22 in a 2,5X magnification micro photo.

Above: brown Baetis, imitation of a tiny mayfly nymph, body length about 4mm. This size can imitate Caenis, but also other tiny Baetis groups like B.Scambus or B.fuscatus.

Another insect group in which nano nymphs do well is the Chironomidae family. Nowadays, in their smallest representatives, the real angler's curse. They are the most common water insects. If you may come across a hatch of Caenis sometimes in your life, in comparison you will come across plenty of Chironomidae hatches. Likely, most of the time, you will not realize it, or you will not have anything compatible in your fly box. In the pictures, nano Chironomidae nymphs tied on microscopic grub hooks.

At times I have been confronted with hatches or pre-hatches phases when the fish would eat very tiny things from the surface or right beneath. In these times, even an 18 size hook would be overdimensioned. Typical feeders on these tiny insects are grayling and char, and big trout are no exceptions. Especially when a large number of nymphs are drifting in the water column.
Picture: A juvenile stonefly larva plays dangerously close to the jaws of a Hydropsichae

Tying on hooks of this size is a challenge. To be successful, the choice of the correct materials is paramount. First the mounting thread. If you used threads like 8/0 and thought it was a small one, well, threads from 20/0 to 24/0 is the right size. The body can be made of mounting thread. I personally prefer to use peacock quill and small goose biots for the back and the wing case. Thorax and legs are made of the rabbit dubbing, which has thinner hair in comparison to hare and is more appropriate for nano nymphs. In all the mayfly nymphs in this article the tails are made of Coq de Leon fibers.

Now, assuming you find yourself while tiny flies hatch and the fish take them in the top 20 cm. of the water column. You can rely on your sight if the light conditions and the surface rippling allow it. Not easy, but definitely possible. For all those cases with limited visibility, a tiny strike indicator is of great help. It can be mounted in the following way: on the terminating part of the leader, about 20 cm in front of the fly, insert the leader into a silicone tube 3 mm in diameter, creating a loop. In the nylon loop that protrudes from the silicone ring, insert a tuft of wool. Pull either end of the leader and the wool will be secured in the sili-ring.

The perfect rod for nano nymph fishing should be sensible and flexible enough to fight with thin leaders, yet powerful enough to handle big fish. My favorite is a 4 weight rod. A good 3 weight will also fit. Above: an autumn evening during a hatch of tiny olives mayflies.