I will say they are good at hiding..... went out to dinner, the lights were still on but starting the ramp down before I left for dinner. Came home and the lights were off, and the 2 clarkii's were no where to be found. Started looking at the top to see if I forgot to close it good, or somehow there was space to escape, and the floor...... got the flashlight and was looking on the counter the tank is on, and around the counter on the floor.... not there..... shined the flashlight in the tank and they swam out from behind one of the rocks and looked at me like they were saying, "umm... what do you want, we were sleeping, stupid"..... Was about to interagate the dog about what he did with them.