I just bought an silver aro and a clown knife about a week ago. yesterday i added a senegal bichir. Today my clown knife is gone. He's not stuck to the floor and there are no pieces of him floating in the tank, i took out his fav root and still no CKF . Did the Aro or the bichir do him in? the aro is approx 5", the bichir is approx 4.5" and the clown "was" about 7". They had been well fed on black worms and carnivore pellets even some krill. Do I have a killer aro? Should i try again? What else can i put in the tank with him?