Well I recently had to seperate my fire eels. The bigger guy had enough of his 20" counterpart. He measures in at 22". Anyway...I moved the little guy into my tank in the kitchen. He escaped and I found him on the floor the second day after the move. Well he was alive that time. A little dryed up but was alive. Returned him to the tank. He was fine and ate later that night. Fast forward a week. He escaped again. This is after i tried to turn my tank into alcatraz. I still can figure out how he got out. The only open area is where my hob's drain into the tank. this is just enough space to where the water can drain in and not catch on the glass tops that I had put bricks on. Not enough space to get my index finger in between. Baffling to me. So just a heads up to new eel keepers.