i made my tank divider using a tutorial, they won't let me post the url but if you google 'DIY tank divider betta fish' it should be the first one, good luck with your sorority! i've always wanted one but sadly don't have the time to make sure it works :(
Hey ManInBlack, where did you find a divider for a ten gallon? I have a betta named Shimmer and I soon hope to upgrade her to a 10 gallon, but a divider would be nice (in case any other bettas come along, which I know they will). I am saving up right now to buy all the supplies for my hopefully soon to be sorority (it all adds up pretty quick).