part of how they grow has to do with the conditions the angels are in..so you won't get many answers.in optimal conditions with in 4-6 months you may have get them to form pairs.
small angels(juveniles) should be fed several times per day.once they hit dime size you should move them from a growout to a larger tank(10 gallons per angel) once they get to quarter they tend to grow fast..I moved mine to main tanks by the time they reached that size..now they are near adult .. but it's difficult to say