<Why do I get the impression the bloke went with some tetras instead of arowanas lol.>
because that's what he did. i think he went with mainly discus. the only aro i've ever seen on that site was a guy who had one in a 75g who said that as long as he kept the water parameters ideal it was happy, i got into a huge argument w/ him about it not having enough room and a couple days later i got banned for getting into another argument with a guy about ethics.