Hi Andy,
If you realllly can not afford a bigger tank and reallly don't want to part with them: LOWER the temperature, bring it down slowly to like 72F. What temp are they at now? They seem to be more inactive at low temperatures. Try puttting a divider, build one, well, hmm if tank is too small dividing tank may Really make them cramped, but you can try dividing with fine-wire mesh trying to somehow maximize their range of movement given the space constraints. With a small tank it's hard to say if there is possibility they may be trying to "pair-up", unless you know you have a male and female. If fights are pretty violent you should separate them somehow. Put one in your bathtub

Good luck, o yea -check the recycler in your area you may vary well find someone willing to give away a 50gallon tank or trade you for something.
Joe
www.cichlidfish.com