Pinheads
If you like to fish tailwaters like the Swift and the Farmington you will need the tiny flies that we like to call midges. Actually they can be Diptera (true flies), tiny Mayflies, tiny caddis flies, tiny aquatic worms and so on.
Hot Spot
The sizes that I fish are in the 18 to 24 range. I don't need to go down to the 28/30 range to catch these fish. I may tie a small fly on a larger hook (28 fly on a 24 hook) which seems to fool them at times.
These flies are effective all year long, especially in the Winter although I've had great success on the Swift's Bubbler Arm on hot Summer days.
Both of these flies were invented on the Swift River!!
Ken