Hi,
i kept my lucius gropu together with a gropu of Trichopodus pectoralis, no problem, the channa knew these fish are too big to swallow at a time. Even when the lucius had babys they did not much harm to the Trichopodus group. I think they only prey for small fish they can swallow at once, other than the giant snakeheqad, who is able to bite pieces out of same sized fish.