I know a PC game has perfectly nice for our very own Betta addicts:http://www.digifish.us/bettabetta/bb_infor.htm
I got both English and boxed Chinese version. It has been developed quite time. The Win98 would run it no problem as I recalled. Due to its minimum ram memory required,you would be able to run in on the screen while doing something else,ergo:wilfing,tasking or typing your home work. Quite like a real Betta tank abutted.
And it got much more than swim in the tank,you would make it stronger by fighting with visual competitor or imported from your friend raised(whom has the same game installed). Or training with kickboxing,picking the diamond game............
It has so much fun,try it on your own. Have any question on this game,I would love to answer you as I know.