Don't count on that. I once had one in a 200 gallon tank with lots of hiding places. This was many years ago, before their reputation for escape artists was well known (to me anyway). One morning, I couldn't find him and figured he was hiding. It was a big tank. About a week later, I found him about 20 feet from the aquarium, underneath the TV stand and all dried up.
I would cover the tank with a tight fitting glass top - and even that is no guarantee. Once they get a little bigger, they can push the lid open. A local fish store had one in one of their display tanks. They ended up having to put bricks on top of the tops to keep it from pushing them open and hitting the floor. I wish you luck.