id also say clowns.... a pair of True Percs will lay eggs often, but again fry are tough.... if you do attempt make sure that there is very little flow in the tank, and be sure to cover the filter inlet with a sponge.... aside from that keep water pristine and all the typical fish keeping advice.
I had my pair of percs lay eggs, and unfortunately none of the fry survived, i think i may have actually OVER WATER CHANGED. I did a partial WC everyday and they all died off over the period of a week. Many of the eggs were unfertilized and never hatched as well... I read an interesting article that focused mainly on keeping water params stable instead of worrying about top of the line quality so much.
Just my experience/advice 8)
-Jay