My most memorable fish is the first one my daughter caught after teaching her how to roll cast. Its not the biggest fish but she had the biggest smile on her face after she brought it in.
Now I have to get her a fly rod because she keeps taking mine every time we go out.
This is another good one. Its a little 6" Largemouth bass that would not hold still for her. It's also the first time I've gotten her to hold a fish.