I suppose its personal opinion but I've found bettas to be highly active. Granted, they are slow swimmers by nature but when given a nice heated, filter tank large enough to swim freely - they're just beautiful to watch. But then again, bettas arn't for anyone.
I believe I know what you mean. Some of my relatives hunt and while they do enjoy it, its not just for sport, everything has a use and saddly central NY and western PA have a shockingly high deer population. I don't liek the idea of hunting and could never partake in in but thats because I'm a squishmish person who can't even get up enough nerve to kill a spider that's been stalking me

Putting any fish together to see a fight in my book is animal cruelty. You're aware of that fact and aware of what you might be tempted to go so thats a good thing - perhaps bettas just arn't for you ^_~
There are plenty of other opinions. I might suggest looking into a school of zebra danios. Their natural distribution would lead me to believe they would work nicely with your theme. They are very active and while most sites say they are top dwellers, I find mine all over the place. What size is the tank?