If you have no room jcon have to make a choice Jack or community. Big Jacks are solo fish. At a friends hatchery she put a 2 kilo mud crab into 10 000 litre round holding tank overnight (was going to get cooked next day) with a 65 cm Jack the only fish in there, next morning only the carapace and a few bits of shell left + 1 fat Jack, even ate the claws.
