These guys are like 6/7 inches and my guess is there total age is 18 months (I've had htem for about a year and purchased around 3 inches). They sure do grow up fast - at least the pair is extremely docile all things considered.
But don't they need a year or 10 before the mature ? In any event they are extremely passive - someone said they were quite aggressive but as long as the other fishes stay about 8 inches to a foot away they don't seem to care much. Those serpae tetra i ahve are just lining the parameter waiting for the parents to leave....