Buy a 40G and buy 6 angels under 6 months old. After they are 12 mon ths old or older, they will start showing aggression to other fish and not another. But you will notice a pair forming and once you do remove the remaining angels. Provide flat vertical surface for laying eggs and even an amazon sword (Plant) may be chosen as a possible spAwning site. But provide at least 3 choices. Feed the fry with newly hatched Baby brine shrimp.