If I'm alone, I'll generally tip $50 to $100 per day, depending on how much effort the guide is putting in.
If we are more than 1 person fishing, we'll generally split $100 daily tip.
I do a bit of guiding in my spare time, about 65% of customers give tips, but rarely over 15%. Rarely exceeds $50 for a $350 to $400 day, but I'm not expecting tips from anyone, nor do I mention it at all, as some of the American guides I've fished with tend to do.