Blaine - I was doing the same thing with a tub last summer; my livewell can really only tolerate 5 or 6 shad max, so I rigged up a bigger tub, running the water to the tub through a piece of tubing from the livewell pump. I think it is a matter of how much room the fish have rather than an issue of oxygen.

Anyway, congrats on a great day; this post got my heart racing a bit!