Only 5 "? Just wait another month. This is the time you will want to remove anything you think can fit in his mouth, even the heater isn't safe. I've seen and heard many stories. At 4" my RTC was taking down 4.5" fat bala sharks. Have fun playing with your pet. But you, like me, might have to find it a more ethical home when it gets too much past a foot (won't be long).