Thread white (black and red for the head and collar) 3/0 for the eyes, 12/0 for the body
Materials
Eyes Silver metal tape (6 mm 3D eyes on 85 lb mono)
Top wing White uni stretch (synthetic Super Hair, tapered ends)
Belly White uni stretch (Polar Fibre)
Flash Pearl flashabou (Ice Dub Shimmer Fringe)
Back wings Black and olive material (Polar Fibre)
Dubbing collars Pearl and silver dubbing collars (Ice Dub in a split thread)
Gill dubbing Fluorescent red ice dub (Ice Dub)
Side flash Olive crinkle flash fine (about a dozen crinkle flash strands)
Cheeks Grizzly hackle (2 saddle hackle tips)
Throat Red buzzer wrap (Polar Fibre)
How to tie it
Start 3/0 white thread behind the eye and mount 6 mm silver 3D eyes on 85 lb mono underneath the shank with figure-eight wraps, then whip finish and cement. Slinging the eyes below the hook is what makes this big fly hang and track level.
Switch to 12/0 thread behind the eyes and build the first wing block: tapered white Super Hair on top, white Polar Fibre split evenly underneath, pearl Shimmer Fringe over that, then folded Super Hair, black Polar Fibre and black Shimmer Fringe, each layer slightly longer than the last.
Split the thread, wax both sides, load pearl Ice Dub loosely, spin it and brush it out hard before wrapping it to the base of the eyes. Brushing before you wrap is what keeps the dubbing translucent rather than a solid plug.
Build the second block around the eyes (white Polar Fibre below and on both sides, olive and black on top) then wrap a fluorescent red Ice Dub collar behind, between and in front of the eyes for the gills.
Add a third short block in front of the eyes, then gather the whole wing and lock everything in behind the eyes with a dozen firm wraps. Set a dozen olive crinkle flash strands along each side, trimmed shorter than the wing.
Overwrap the white collar with red thread, trim the wing butts to a taper toward the eye and cement, then add a final silver Ice Dub collar, a last short white/olive/black wing block, grizzly hackle tips on each side and a red Polar Fibre throat.
Build a black thread head, whip finish, cement, and once dry coat the head with five-minute epoxy so it survives being cast on a big rod all day.