Waterhen Bloa: How to tie & fish this “Blinged-up” beautiful Old Classic

The Waterhen Bloa is a classic North Country spider fly pattern that dates back over 200 years (originally known as the Dark Bloa and a few other names).

It has been one of my favourite trout spider flies since I started tying and fishing it on the River Wharfe half a century ago.

A few years back I read an article by Paul Proctor where he’d modified the fly by adding a pearly butt. I’ve tested his modern version on the Welsh Dee, and the results have been…

nothing short of Spectacular.

To the extent that, now, I almost exclusively fish the Pearly Butt Waterhen Bloa.

Once the Large Dark Olives appear on the river, this fly catches trout. Also, it continues to work until the end of the season whenever olives are hatching.

So, let’s take a look at…

How to tie the Pearly Butt Waterhen Bloa

Tying material list:

• Hook:       #14 & 16 Kamasan B402
• Thread:    Waxed yellow silk
• Butt: Three turns of Mylar tinsel
• Body: Natural mole fur very lightly dubbed
• Hackle:     Waterhen wing undercover feather (Starling is a reasonable substitue for Waterhen)

Step-by-step fly tying instructions:

Step 1. Place the hook firmly in the vice and start the thread 1mm behind the eye. Wind the thread down the hook shank in touching turns and catch in a length of Mylar tinsel opposite the hook point.

Step 2. To form the pearl butt, wind the Mylar tinsel towards the hook bend and back to the tying thread. Secure the Mylar with the thread and trim off the waste.

Step 3. Wax the silk thread and sparsely apply some mole fur dubbing to it. I achieve that by just touching the thread with the mole fur. You should be able to see the thread through the fur.

Step 4. Wind the thread up the hook shank to about 2mm short of the eye. You should be able to see the thread through the dubbing. When wet, the two layers of light and dark will blend perfectly.

Step 3. Prepare the hackle by removing unwanted flue from the stem base then gently stroke the fibres forward to rest at right angles of the stalk. The fibres should extend just past the bend when tied in. Tie in the tip of the feather with a few turns of waxed thread.

Step 4. Take hold of the hackle butt with hackle pliers and wind on two and a half turns towards the eye. Tie off the hackle with a couple of turns of waxed thread. Finally, form the head with the thread, whip finish, and apply a drop of varnish to the head.

There seems to be a lot of debate on how many tuns of hackle to use when tying soft hackle flies. All I will say is that I’ve caught fish on flies with one turn of hackle to three turns.

Recently Waterhen (Moorhen) wings have been difficult to source, When they’re not available, I’ve tied the fly with a variety of pale-grey, soft feathers, and they still catch fish.

Also, I tie variants using the feathers from the outside (marginal covert) of a moorhen wing, which seems to work just as well as the traditional patterns.

Fishing the Pearly Butt Waterhen Bloa

Generally, the literature mentions that the WB is used during the early months of the trout season. It is a good representation of hatching Large Dark Olives and works best on cold, damp days when olives struggle free of the water surface.

For me, it’s much more than an early-season fly because I catch trout and grayling throughout the year.

So how do I fish this spider…

Equipment-wise I use a 9ft 5# rod, a floating line, and a 9ft 5X copolymer leader, which has been cut back to 5ft from the butt end. At the end of the leader, I tie on two 3ft lengths of 3lb copolymer to form 2 droppers.

The Pearl Butt Waterhen Bloa is fished on the top dropper of a 3-fly cast from March to mid-April. Often with a pheasant tail nymph on the point and a black hopper on the middle dropper.

As the season progresses the black hopper is moved onto the point, and either a March Brown spider, Snipe Bloa, or Orange Partridge is fished on the middle dropper.

Wherever possible, it’s best to fish these spiders up and across the stream on a leader that has been degreased with fuller earth to ensure it sinks.

Finally, I hope this article stimulates you to tie the Pearly Butt Waterhen Bloa and test it on your local river or take a trip to fish the Welsh Dee where this North Country spider will catch trout and grayling throughout the year.