The tried and true method of getting a pair is put 6 juvies in a 55 gal and grow them up,your almost certain to get at least one pair. You wont really know its a pair until eggs hatch cause sometimes 2 females will pair.The reason they pick a strip of slate or heater tube is in the wild they spawn on broad leaved plants,you could also put some plastic or real giant saggitaria in there.The only reliable method Ive ever heard of to sex them is when spawning the female will have a wider blunt egg tube while the male organ is thinner and pointed.
