Not long ago, I received an email in which a customer mentioned "micro nymphing." Reading it was like a jolt. I have fished for micros with tiny nymphs more than a few times and for more than a few years, but I never thought of it in the way he described it in his email.
If you do an internet search on "micro nymphing" you'll get a couple hits describing fishing micro nymphs for trout. That is not what he described. Not at all.
Most of his fishing had been Euro-nymphing or tight line nymphing for trout. He lives too far away from a trout stream to fish as often as he'd like so he started micro fishing in the small local streams.
Although his micro fishing started out as just a way to go fishing more frequently and closer to home, he realized that it had another significant benefit. It made him a better Euro nympher!
He wrote that when micro fishing, he uses the same techniques he uses on a trout stream, but he does it with size 26 flies and a tenkara rod. (I think he uses a Suntech Kurenai HM30R which is actually a seiryu rod - and is better suited to micro nymphing than most tenkara rods).
His view is that there is no better way to sharpen Euro nymphing or tight line nymphing skills than by getting good drifts with a size 26 nymph and detecting subtle strikes from micros. In his words, "I bet when the tight liners figure out how much better it makes their normal Euro nymphing, most serious guys will flock to it."
Most of my own fishing is not tight line nymphing or Euro nymphing. However, I can certainly understand why he came to that conclusion. I have had a few experiences that really highlight the sensitivity required to fish micro nymphs for micro fish.
Perhaps the most dramatic was on a day I was fishing a salt marsh with Coach. We were both fishing the exact same fly, a black Killer Bugger with a white glass bead head. He was fishing his "go to" Suntech Kurenai HM39R (12 pennies) with a size 3 Sunline tenkara line. I was using a Nissin SP 390 (8 pennies) casting a line the diameter of 6X tippet with a single Dinsmore size 10 shot to provide the weight needed to make the cast. It was one of the few times I soundly out-fished Coach.
The Mummichogs we were fishing for were too far away to see the white bead head in the water, and they were too small for Coach's size 3 line to register the strikes very often. They were plenty large enough to cause my 6X line to hesitate or twitch, though. The 6X was a hi-vis Ayu line, but hi-vis 6X is an oxymoron. The line is too thin to see very well no matter what color it is. On that day, though, the light was good and I was able to see the hits.
Fishing with a line that is light enough to register the take of a micro is key. They do not smash your fly. To call the strike a "tick" is almost an exaggeration. It's not quite imperceptible, but it is extremely subtle. The lighter your line, the easier it is for a micro to make it twitch.
Use the lightest line you can cast.
Earlier this fall I was fishing a stream in which the water was very low and very clear. I was fishing a light colored wet fly and towards the end of the drift I could see the fly clearly. The stream has excellent natural reproduction and there are lots of small trout. I was surprised how often I saw the fly lurch an inch or so to the side. That had to have been caused by young of the year trout, which were large enough to hit the fly, but too small to hook very often with the size 12 I was fishing.
When fishing either wet flies or nymphs, I am sure we get many more hits than we either see or feel. Fishing with a very light line, a very sensitive rod and flies small enough for micros to take has to help condition the senses and the reflexes.
Sight fishing is more easily done when fishing for micros than for trout, largely because the water is often much shallower. When fishing close by and in shallow, clear water, I have found it to be very useful to use a white fly.
Micros don't seem to care what color the fly is. The gold bead on a a black Killer Bugger does make the fly somewhat visible, but a white fly really stands out against a dark stream bottom. You often can't see the fish, which have excellent natural camouflage, but you can often see the white fly just disappear. It disappears into a fish's mouth!
That said, I do have one customer whose "go to" fly when fishing for trout is a white killer bugger because he can often see it and see the take.
Depending on where you are fishing, your target species may be small sunfish. If not, though, and if there are sunfish in your waters, you might not be able to get past them to reach your target. Small sunfish are voracious. If they're there, you'll catch them micro nymphing (whether you want to or not).
Most of the micro nymphing I have done has been with a bead head Killer Bugger. The bead has almost always been gold tungsten. As mentioned above, the gold helps a bit in watching the fly.
The tungsten bead adds just enough weight to help cast a very light line and very light tippet. It also helps get the nymph a little deeper. For that matter, with a size 26 fly, sometimes the bead is needed just to break the surface tension!
I have fished with unweighted Killer Buggers, though, and have caught fish with them.
I have also caught fish with unweighted Pheasant Tail Nymphs. A size 26 Pheasant Tail Nymph is harder to tie than a size 26 Killer Bugger, though, and a Killer Bugger has been plenty effective.
If you love tying flies, by all means, tie size 26 Pheasant Tail Nymphs. If you just love to catch fish, though, tie Killer Buggers. Of course, other simple patterns like an Al's Rat or Zebra Midge work also. I have not found micros to be particularly picky, so there's no need to carry a box full of different patterns.
Euro nymphers will often fish a pair of nymphs. I don't think I have ever done that while fishing for micros. The closest thing I have tried is once fishing a small unweighted Stewart Black Spider on a dropper and a bead head Killer Bugger as the point fly. Both flies caught fish, although not on the same cast.
When fishing for trout, I have caught fish with a size 26 bead head Killer Bugger, but only in a small stream at a low water level. I have also fished a couple streams where the 26 didn't draw strikes but a 20 did. My guess is that the 26 just didn't get deep enough.
For many micros, you don't need to go all the way to a size 26 or smaller. Coach and I have caught more fish and more species with a size 20. For very small micros, you would need the 26.
If you are fishing for micro fish, use micro flies.
Most of the fish I have caught with micro nymphs have been caught wth seiryu rods. Most but not all. On one trip to North Carolina for a Tenkara Jam we had all fanned out to fish one particular river. I learned that a small tributary had a good population of Warpaint Shiners, a species I had never caught. I didn't have a micro rod or even a seiryu rod with me, so I used my TenkaraBum 40 with my lightest line and smallest fly and was able to catch a few.
Whereas a Kurenai HM30R might be a more obvious choice for micro nymphing, one advantage of a rod like the TenkaraBum 40 is that you could use the exact same rod and line when you are Euro nymphing. That way, the "sensitivity training" would be directly applicable to the "real" world.
But you know, even if you're not a dedicated Euro nympher, micro nymphing can improve your senses and your reflexes. The strikes really are subtle. And if nothing else, it will help to mitigate overly aggressive hooksets. You definitely do not want to spend your day searching the weeds behind you for the little guys you launched over your shoulder.
More than all that, though, I think you'll find it to be an enjoyable challenge. Plus, of course, micros are everywhere.