The Disco Midge is a flashy take on the classic midge larva or pupa. Where a Zebra Midge keeps it drab, the Disco trades the thread body for a wrapped strand of pearl Krystal Flash or tinsel, so the whole body glints. That sparkle reads as the gas bubbles or sheen on an emerging midge and pulls fish in slow, clear water where a plain fly gets ignored.
Tie it small - sizes 18 through 22 - to match real midges, which run tiny. Red is the workhorse: it reads as a bloodworm and as the blood-red thorax of a developing pupa. Pearl and silver are the brighter, more attractor-leaning options for stained water or low light.
Fish it as a subsurface nymph, dead-drifted through the water column rather than skated under the film. It shows best in cold water, 38-55F, when midges are the main game and bigger bugs aren't hatching - dead of winter and early spring on tailwaters especially. Run it on a dead drift, often as the trailing dropper below a heavier point fly or under a small indicator, in low to normal flows. Keep the tippet light, 5X to 6X, so the small fly drifts naturally.