I really go for “sippers” in slick water !! It is my passion. As long as fish are sipping and not spooking, I will stay with them until I put them all down.
The tailwaters that I fish in Tennessee have a lot of long “slicks” with midging fish. My dry of choice is the Griffiths’s Gnat, sizes 20-24. A black ant of size 20 can bring’em up for a look too.
One of my favorite games is to use a small dry fly and “drop” a sinking midge pupa down under it about 8 inches with 7x tippet. Ex: Use a floating Blue Wing Olive, size 16 or 18………. something that will not cause a lot of alarm to the fish when it passes over their heads. I attach a piece of good 7x tippet with a clinch knot to the bend of the dry fly hook. I then drop any of a number of midge pupa patterns that sink about 8 to 12 inches under the dry. I use a hook heavy enough to sink fairly fast, like a Daiichi 1150. It is made of heavier wire and is a “scud” type hook.
The patterns I tie are mostly my own, but most are based on a thread body like black, red, or brown. Some I will spiral wind with spaced fine gold wire. Some I will simply place one turn of peacock at the head. A new one I have just started using really looks good. Some call it the MERCURY MIDGE. It uses a Daiichi 1140 (midge larva hook – only found in small sizes) in #18, 20, or 22. It has an EXTRA SMALL silver glass bead on the head. The body is black thread. The rib is extra fine gold wire, spaced so that it has around 7 turns from back to front. It looks wicked. It actually matches a lot of the midge pupa found in every river and in the bottom of my raft after each float trip.
I time the rising fish for a while. When he has fed, I will wait about 10-20 seconds, then pitch the rig in its feeding lane a few feet upstream (3′ – 4′ ?). This gets the rig away from him a little and gives the nymph time to sink to the end of the short dropper line thereby giving the best “telegraph” of the strike. When the dry passes over him, he will usually show a take after the dry is about 3 inches below the center of his last riseform. It is really challenging and a fun way to fish, but a lot of patience is involved. Then comes the 7x: You have to play even a 12 inch fish like he was a monster. After landing 2 or 3 fish like this, I always change tippets because it stresses that little 7x stuff.