A lot of people keep them here in Australia, have a look at the ANGFA and Australian native fish (I think that's the name. Murray cod picture) facebook groups and ask around. Most people keep them in freshwater, but they still get big 1m+
I have kept both the golden and platinum variant in freshwater for several years as they aren't too hard to find here in Australia,they can live in freshwater there whole life and usually only go into saltwater for breeding purposes but they get huge easily reaching 90cm+