Pound for pound..(Prosopium williamsoni) or the mountain white fish do fight harder than the suckerfish common to our rivers. Have caught some 18-22 inch YT's while fly fishing on the east side.. They can fool you for a couple minutes.

A few years back side drifting the cowlitz for steel I landed a YT that had to push 5lbs... fought much better than the suckers you can occasionally hook down there of similar size.