Sounds about right, I have done reserch on Tilapia,for human consumption most are farm raised and used cyclical in ponds to clean and rejuvinate them, one season catfish,etc.. will be raise then switched the next for tilapia.They do grow fast depending on the food source,most are feed assorted pressed meal pellets.Most farm raised fish will all be netted at a certain point so that pond will only produce the species they want without a mix of fish.