Without a doubt, a female Aru I had was absolutely the most demonic Chondros I've ever owned. I have a few Biaks and they don't even compair to the Aru. Arus are said to be the most calm, but I have also heard from others of the "odd" nasty Arus.

Overall, the best bet would be to get an older established animal who's temperment can already be determined. In my experience, captive bred animals are pretty easy going in most cases.
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