They stay fairly small but you need to make sure you get them from a very reliable source as there are lots sold as dwarf but arent, also some claim the parent is a dwarf purely because it didnt grow very big but normally that is down to its diet. Some claim they are het for this or that, if that is the case them they arent a true dwarf breeding so they have the potential to grow to full size. dwarfs also have a different marking to normal.