Watched our 5 y/o Dachshund learn to swim in it. He's an obsessive hunter & went in, chasing after a frog. Not sure he's exactly comfortable with it, but it certainly didn't freak him out enough to keep him from doing it a couple more times today. Don't know if our older female Dachshund will go in or not. She'll romp & run after the frogs & put her front paws in the water while she sniffs & watches, but hasn't gone in after one yet. She's a stone killer, but isn't the spazzed out psycho that the younger one is.