They look like they're decently sized already. Best advice would be to have a big tank(preferably 125 gallons or more for a growout), 40%-60% water changes twice a week, temps of 83-86 degrees F, clean water and feed feed feed! Are they on pellets?
Yes, they are currently on hikari massivore and occasionally market prawns. Trying to switch them to hikari canivore pellet as i just bought it today. Any advice on choice of pellets too? =p New to pbass. Fell in love with their colouration and behavior.