You make up a name and BattleFishies generates a BattleFishy. Put your BattleFishy's name in the input box of any other BattleFishy, hit "submit," and, voilà, you find out which fishy is the toughest. Or as BattleFishies phrases it
If you want to test it out, see how PsychoSwimmer stacks up against BetaBlaster.
Two fishies clash.
The Aquarium is too small.
There can be only one!
I don't know if there is anything to be read into this or not, but the BattleFishy named George W Bush beats BattleFishies named John Kerry and John Edwards easily, but against BattleFishy Howard Dean, it is a tie.