i juz restarted keeping aro back just this yr..new coloration of reds/golds/xbacks...so many to choose from..from my experience n my observation since 12 yrs ago..these are purpose of what food is for your aro.

frog = rapid growth
live prawns = enhance natural redness
centipedes = enhance coloration of fish(regardless of color)
bird worm and market prawn = for making ur fish 'thick' and gd growth ( i feed 2-4inch aro with these and it can grow twice its length and broadness in 3 weeks)
fishes = juz to make the aro 'full'

my food menu for aro:

2-4 inches = bird worm
6-9 inches = frog + market prawn
10- 14 inches = frogs + market prawn + live prawn
15 inches onward = market prawn + centipede + normal fishes(if u have tight budget..hehe)