My parents got this as a nail file for me when I was a kid. It was only many years later whe I got into monster fish I realized it was from a 'paima. Next to it is a dried scale off a 32" arowana.
The dark grey part is what you see. The rest overlap each other to give a great armor protection for the fish. If you would cut straight into an arapaima, you'd see that the entire body is 4 or 5 scales think.
