Just bought a fish - it was sold as a Panoon Shark and said it would grow to 5 or 6 inches .!!?
It doesn't seem to exist on the internet .
It looks like a young 3" arowana to me - it cost £8 or 12 Euro .
Stays in the top third of the tank and is very fast .
Sorry no pictures as yet.
As I said it looks similar to an arowana - but silver with a blackish horizontal line halfway down