What tippet size should I use?
This is a question I have heard time and time again when I worked in fly shops, when I guided or when fishing with friend. The answer is, “it depends”.
There is no one size fits all rule for tippet size. You choose your tippet size based on a variety of factors. Things to take into consideration are the technique you are using, the conditions you encounter and the fish you are targeting.
Here’s my take and a starting point. An old general rule I learned was to start with the “rule of 3”. This rule instructs you to divide your hook size by 3 and that is your starting point. So a size 12 would be 4x, a size 18 6x and a size 2 would be 0x or bigger. I think this gets overlooked a lot particularly on bigger flies and people fish tippet that is too small. As a result, knots don’t hold well when you have narrow diameter tippet trying to cinch down on a large diameter hook wire. I don’t actually do the math, but have a baseline in my head for the fly size. At any rate, this is the starting point then you refine based on technique and conditions.
Say you are fishing dry flies to rising fish in shallow clear water, which would make the fish more selective. In that case you would size down, so if the bugs you are trying to match are a size 12 the starting point is 4x, so size down to 5x. If you are fishing size 2 streamers in deep off colored water, the starting point is 0x so you could get away with pretty heavy tippet at least 01x or bigger.
In addition to this baseline, I also try to fish the heaviest tippet I can get away with since we don’t want to play fish to death and don’t want to break them off either. In general, I usually fish 5x for smaller dry flies and nymphs (16-20), 3x-4x for medium sized nymphs (10-14) and 2x and bigger for streamers (1 or bigger – 8).
I rarely fish 6x unless I’m fishing small BWOs, tricos or midges to very selective risers. Honestly, if you dial in what they are eating and get the right fly you can get away with a lot bigger tippet than you think. Conversely, if you don’t dial in what they are eating, then fishing the lightest tippet possible isn’t going to get it done either.