Not a Diamond, but a Pennant fish.

[Shortlite]

Almost spot on with the differences there Jeff. I have caught both, and the Diamonds also have black trailing fin filaments. You can see them in your picture: often when the fish is out of water they tangle up. The diamond, as you mention, has a steeper head and angular "bump".

I also caught a juvenile diamond trevally today funny that!

When both species mature they lose the filaments, more so in the diamond than the pennant. As juveniles they often associate with stinging jellyfish: the filaments aid in mimicry.

[jenz]

That's a very pretty fish. Beautiful in fact. I'd love to catch one. And release it of course. well done ffejsmada.