its definatly a trevally. strong and fast swimmer. firm meat, so the spear doesnt rip out that easily, but a fish that size, its important that you stone it, otherwise you mite be in for a ride. i once shot one that was a quarter its size and it nearly ripped the gun out of my hand.
have fun and be safe.
ps. check out
fishbase.org you can search using local names and so forth
