Fiji runs on 240 V at 50 Hz, with sockets following Type I. 240 V means no voltage converter – only the plug shape matters.
Handy for multi-stop trips: Tonga, Tuvalu, Niue and Australia use the same plug types. Nearby but different: Guam, Palau and the Marshall Islands – an adapter for Fiji will not fit there. In Oceania, 13 of 18 recorded destinations use exactly this combination.
Protective earth
Grounded socket systems are common
Protective earth is standard in Fiji; your adapter should carry it through.