I've got a 9 inch Jar that will kill anything that I put in the tank with it. Except a pleco who he's been with since I got him. He tries it on with the pleco but can;t fit into his hiding places so hasn't managed to get him. Yet. And a large snail but the snail is pretty well protected I've tried all sorts with him, Pacu, Oscars, Gouramis etc and even if they are larger, they end up with shredded tails and bite marks on their side. Jardini is not a community fish IMO.
He currently lives in a tank that is 140x50x50(cm), but in due course he'll need something bigger I imagine.