I've had black ghost knife fish for many years only 1 at a time but mine dose very well in plan site in clear tube closed on one end and the other I plants towards back corner so he can squeeze in and most others can't I use frozen blood worms and stick the cube into his tube led color changing lights keep the tank lit so I can see fish and not so bright for knife I'm not sure how to answer specific posts for help as I'm new to posting in any forums so hope those that had question on their knife see this