I highly doubt that you had other fish inside the tank with the arowanas and they lived in harmony. The many tanks I've seen have the other fish hiding for their lives in fear of those fish. They eat all fish you put in the tank rather quickly (one at a time). (It's an impressive sight to see.) Now, if you are talking about the baby arowanas, they can be in a tank with larger fish and they aren't too bad with them until they get hungry. It would be nice to see a baby one in the tank though. Arowanas are hard to maintain because they need extra care and die if they are mistreated (tapping on glass at petstores).
I checked out your website and found this link to be what you probably intend for mixing awrowanas..
http://www.arofanatics.com/index.php...ankmates01.mpg
That red parrotfish is one mean fish also..