One thing I've recently tried which has made my shots much better is to use "Sports" mode on my Optio. It's a faster shutter speed and keeps my shots from being as blurry as they are when I just use plain "Green" mode. Now, about your actual question.. I do just what you do; hold the fishies out at arm's length and hope.
Oh.. get a strap for that Optio and attach it to yourself or your kayak.
My Optio takes some pretty good photos of flies if I put it in macro mode and use a tripod and good lighting.
Enjoy!
"If I'm not going to catch anything, then I 'd rather not catch anything on flies" ... Bob Lawless