I had a link showing an 8 ft wild aro on my laptop, great link, it was aro info, fanstatic, my laptop is a little upset right now, I'll try to recover. I've talked to a few people who say their have reached 3.5 ft in the right size aquarium with large tank and room to really grow. They're going to adapt to their enviroment to survive. I let you know, mine was a few inches in September and now over 18" and growing really long really fast, like before my eyes!!!!
You sure the 8' wild one wasn't an arapaima? That is way bigger than any recorded arowana.