OSA Nymph

Published Jul 8th 2014

A generic nymph that can do equally well as a stonefly or mayfly nymph as it can a waterboatman or backswimmer


OSA nymphs

This fly have caught many trout and yellowfish for me, over the last couple of years.
It is one of my 4 or 5 top goto flies, and when I start fishing I often tie on an OSA Nymph.
It is a general mayfly to stonefly nymph profile. The black bead and abdomen, gives a very good profile against any background and in any light conditions, with the UV dubbing add a different depth, dimension in the light and in the light spectrum.

I paged thru some old magazines, the other day, and saw the TVN nymph, and thought there is something similar to the profile and color of the TVN nymph, what could be another reason for doing so well with the yellows.


It has also produced a good number of fish on still waters. When I was looking at the water boatmen, backswimmers and corixia images on the net the other day, I realised why. The basic profile is very close to the water boatmen, backswimmers and corixia. But the UV thorax, makes a very good air bubble impersonation.

Perhaps, for most fish, it looks, just too much like food, to not taste it.

What's OSA for a name anyway?
OSA is a fly named after the Old South Africa (apartheid, definite segregation etc). The fly being distinctly black and white mixed with brownish colors it's a reflection of SA as it was. We had black people, white people, the copper wire was for the Indian/curry and the pheasant tail was the colored or brown people (people with mixed parents, black and white) and the tungsten bead is all the hard headed people in South Africa.
All of this might not make sense if you don't know too much about SA, apartheid etc.

OSA Nymph
Korrie Broos

Hook#8 to 18
BeadBlack or gun metal black
WeightLead or tungsted wire
Tail6 to 10 Pheasant tail barbs, depending on the size of the fly
RibCopper wire
BodyBlack possum or squirrel dubbing
ThoraxWhite UV Dubbing

Tying instructions
  1. Place bead behind hook eye, and wrap the optional lead wire behind bead.
  2. Tie in Pheasant tail in as tail and leave the long butt section, as this will become the legs.
  3. Tie in the copper wire.
  4. Apply dubbing and wrap over the pheasant tail fibres, to about two-thirds up the hook shank.
  5. Rib with copper wire and tie off copper wire.
  6. Lift pheasant tail fibres up and dub thread and under the pheasant tail fibres to bead.
  7. Backward and forward wrapping of the UV dubbing can be done, to attain the right density, covering shape of thorax.
  8. Take pheasant tail barbs over UV dubbed thorax and tie in with 2 or 3 wraps behind the bead.
  9. Split barbs in equal numbers and fold to either side of bead/body.
  10. Tie the barbs in at about 45 degrees to body and whip finish.
  11. Trim the barbs about two-thirds of the overall length of fly.

Step 1 - tail, rib, herl - Start the thread, tie in the tail, trim butts and tie in rib and peacock herl
Step 1 - tail, rib, herl
Step 2 - weight - Add some weight behind the bead
Step 2 - weight
Step 3 - wrap herl - Wrap the herl forward two thirds of the shank and tie down. Leave the butts
Step 3 - wrap herl
Step 4 - rib - Wrap the rib forwards i 4-5 open turns and tie down
Step 4 - rib
Step 5 - thorax - Dub the thorax with flash dubbing
Step 5 - thorax
Step 6 - wing case - Pull the herl forwards over the thorax and tie down
Step 6 - wing case
Step 7 - separate herl - Separate the herl in two parts and pull to each side
Step 7 - separate herl
Step 8 - pull down - Pull down the herl and wrap over it a couple of times
Step 8 - pull down
Step 9 - ready to trim - The legs are ready to be trimmed. Once done, whip finish, cu thread and varnish
Step 9 - ready to trim

Top and bottom

The author and originator

User comments
From: Korrie · korrie·at·caneworld.co.za  Link
Submitted December 8th 2014

Tony, this fly is equally at home in stillwaters and rivers. The profile, shape and size can be so many insects, that fish very seldom swims past it, without taking a nibble

From: Tony Watson · witkoppex2·at·gmail.com  Link
Submitted December 6th 2014

It seems to me this fly would be primarily for stillwater or do you find it equally at home on rivers?

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