Hey Greg,
The use of hormones has some serious, long lasting effects on the fish. The most telling of these is that female fish will generally display male characteristics, and the heavy hormone use damages or stunts their sexual organ development. They wind up looking like your aunt with the mustache forever.
Such fish are usually not capable of breeding, though they may have limited success depending on how much damage has been done.
In male fish, because they have been "juiced" at an early age, and effectively forced to develop their sexual organs and characteristics, they'll often have reproductive issues as well. Think about what happens to a baseball player when he uses steroids -- the same happens to the fish. Because of the age of the fish, they may or may not be able to recover it from it -- these organs were "in development" when they were rushed.
With that being said, if you separated a really nice male out of a group of juiced peacocks, and grew him up in isolation (or with a handful of females), with good water quality and good food ... he'd probably wind up looking okay, he just may not breed. Of course, you may also separate out the biggest, nicest male from the group and find out, four or five months later, that you have the biggest, nicest female (with a mustache).