This is a major factor most people attribute to their challenge in spawning them. They see a large fish and asssume it must be mature. I have kept a frontosa to almost 10 years of age, and heard stories of much longer, like a 14 year old breeding pair. In the aquarium they adapt readily to good quality prepared foods including flake, pellet and frozen foods. I generally maintain them as a species in large groups, this is how I believe they show best.
Peacocks work well, pairs of med.
Not much can rival a 6ft aquarium with 8-10 mature frontosa. I reccomend more than one male in a harem of females. The males when kept singly have too much time on there hands to burden the ladies. I belive this displacement of water makes the point of who has strength and is dominant. I don't reccomend sharp infrastructure for these fish like rocks or thin-lipped PVC, they are very deliberate slow moving, but are prone to dashing when spooked or at feeding time, when injuys may result.