Okay, me and the grandson are puttin' a hurtin' on the trout! I tend to fillet them with 4" and 6" Rapala fillet knives. I'm sure there may be better, but these are quite satisfactory. It seems if I'm cleaning lots of fish a touch up or two during the process is in order. I'm good free-handing and have a Lansky kit, but due to the softer metal and flexible blades they aren't the best choice and time is of the essence. The quickest and easiest method seems to be a few strokes through the ubiquitous pocket "mini-sharpener" with two crossed ceramic rods. There are at least a half dozen manufacturers of these things (but info seems sketchy what the fixed angle is). I have several ( Lanky, Smith's, Rapala, one and two stage). Just eyeballing the things because I'm to lazy to dig out a protractor, I'm guessing they're all around 25 deg., which would probably be the best "one size fits all", prevent offering them in more than one angle option and keep picky sharpening folks like me from shunning them. Anybody know of one that has fixed angles of less than 20 deg.?