they're all big but the smallest by weight would be the leichardt
and poss. the easiest to keep although thats a broad statment
in oz they are regarded as the beginners aro. but they're also the cheapest too at $40
yes, just the baby ones. i even read once that arowanas and other ancients when kept in optimum conditions wont stop growing. slower when they get old ofcourse but they dont stop growing until the day they die. like snakes and crocs. i dont know how true this is but i kinda believe it