I make my own "Quick strike" rigs which are two hooks (usually trebles) tied in tandem.
I have used treble hooks as small as #20, but I have now set a personal limit to #18, mostly for quality issues.
Here's what I use for each species:
Panfish and Stocked Trout = #16 to #18
Walleye = #12 and #14
Pike = #8 to #10.
Of course this is not etched in stone. If I am on a lake that has large walleye, I will drop to a #8 hook no problem.
Same goes when I fish for Pike. If I am on a lake that is known to have larger pike, I will use a larger hook (and larger bait)
I stumbled on the small treble hooks a few years back.
A friend of mine was taking me to his favorite trout lake to do some ice fishing. He kept telling me over and over, " You got to use small hooks or you ain't going to catch anything."
Well, I went to Gander Mountain, to buy some small hooks.
While there, I spotted some #20 treble hooks and decided to be a smart a$$, so I tied up a couple of leaders with floroucarbon line.
I did it as a joke, but at the end of the day, I had 4 brown trout (one short of my limit) and my partner got skunked.
I really like the small trebles because they don't kill or interfere with the movement of my minnows.
Here's a pic of a Splake that I caught last winter and entered into the Ice Shanty online Tourney. *8 lb Flourocarbon, and #20 treble hooks.
Here's a better one from home.
Hope this helps,
Wiener