I have a 50/50 on most memorable fish, well, a number of memorable fish, I'll do 3 haha
1st; My first fish is my first atlantic salmon landed on the fly, although it was a spring fish and not fresh by any means. I had been given reports by a few friends that the fishing was great on this river, my friends had each hooked plenty of fish. So being all excited by their news I made the trek to the mainland to fish. When I got there the river had blown out, the water was raging, 80km/hr wind gusts, -5 and snow. That didn't stop me, it was a couple days of chuckin and duckin and ice cube toes. I had found this pool, but it was too dangerous to cross and fish it, so I walked down river a km or so, at the tail end of the pool, mid swing, something very angry attacked my fly, 15 minutes or so later I tailed the fish myself, took a picture and sent him on his way, he was stunning, even if he was a little lanky, a solid 34" fish
The other two were fish lost, one was a brief, terrifying, amazing experience with one of the monster rainbows that lurk in the depths of our rivers, a fish in the 10 pound range that took me to my backing and whooped my butt in seconds!
The last was a salmon I hooked on the last day of the season, hooked one in the same spot a half hour prior, hooked this guy but he decided to jump into an alder bush, getting my line tangled and ultimately snapping my leader!