I have got Xingu I. Put it in the large tank with lots of tankmates when it was about four inches.
It is now about twelve inches, and is beginning to chase similar sized fish away. It has not attacked anything else yet.
I am keeping my eye on it. It looks incredible. Its color faded a bit as it grew, but now it seems to have coloured up a bit. It seems to have a nervous twitch where it will flex its fins.
I do love it, but I am not sure I trust it.