When the lights go off, the RTC and other whiskery fishes go on the prowl all over the tank. It will start with some splashing that wakes you up. You'll use a flashlight or turn on the lights to see what's up. You'll notice split fins(usually on the rear 1/3 of the Arowana) and maybe a missing scale or two from the Arowana. That will continue to happen until it gets mauled finally, when the RTC catches it. It will either be dead or shredded at that point. That's after the same thing happens to the clown knife. They grow a little bit slower. That's just my humble opinion. Been there, done that 20 years ago. The best thing to do is at the first sign of what I mentioned earlier, move the RTC. Don't wait thinking it's a one night deal. I'm pretty sure that it will happen at some point, so just be aware and ready to take action when it does. I'm almost positive that it will happen exactly like I mentioned before. It always does. Hopefully you will never have a problem with anything.....but if I was a betting man! Good luck friend.