My dream fish is a silver arowana and my dream tank is the 180g. Only reason I will not get the aro is because I've seen them in a 6ft tank and it does not look comfortable. Think of it as you in a jail cell 8x10ft for the rest of your life. That sucks! Now if I was to make a pond that would be a different story. 8ft tank would be nice but still when the aro is FULL grown it is still not comfortable. Word from a non aro owner
Silver aros need lots of room to swim, so the recommended tank size should be a least 3x the length of an aro. Once that aro reaches 30"+ that 6 footer is really too small. I'll be moving my silvers to a 6' x 4' x 2' tank, well see how that goes.