Help With FISHIES!!!!!!!!!!!!! URGENT!!!!!!!!!!!!!!?

Ok, I got a tank (duh) and it's about medium sized. It's about 2 1/2 feet wide and 1 foot tall. I want about 5 fish. I would love all the fish to be different colors. The fish should be freshwater. And I need some tips on how to take care of them. Help is greatly appreciated. Thnx.