Yes a lot of people call Mangrove Jacks, Red Snapper thats the problem with common names, a kingfish in Australia is not what a kingfish is in America.
I have had 2 tussles with really huge MJ's one at night when he took the lure about 8 feet away from me and ran the entire length of the jetty proceed to Rub the leader on the corner at the other end, I could feel it. then cut through the leader and when I got the other half of the leader back the swivel just disintegrated in my hand, it fell appart into crumbs. I have never experienced anything like that ever before or after. The swivels were top quality Yo-Zuri ones.
On that same trip earlier that day my father-in-law hooked into a 2 - 3lb GT. After the GT came a huge MJ he was all lit up and swam around the guy saw about to hit and then dissappeared into the depths, I immediately changed lures to a 6" lure, he took it first cast, but considering I was only using 6lb line and the terrain I did not stand a chance the cut me off on the very first run.
Poppers while they work sometimes on Barramundi they do not work with MJ's, as they like to take slightly below the surface.