never use fish net, use bigger fish plastic bag the size is depends on travel distance and time. put the bag in the tank first, fill in with water, have the arowana swimming into the bag, make sure it enter with head first, dont chase from the tail that may scare the fish and cause it jump. as it fully enter the bag you have to close the opening otherwise it may jump out. the aro will usually jump either the bag is too small or there isnt enough water inside the bag.