"You know, I've never seen the fish use the stairs."

My neighbor very sweetly said this to my 3 year old yesterday. My son was admiring their fish and the tank and the various objects that were in it when he noticed that the bridge had steps. He peered closer, looked at the fish, looked at me and asked, "Does the fish go on there?" My friend, who is well-equipped with 5 children of her own, very thoughtfully replied first. My son just looked at her and said, "Oh." I, on the other hand, was going to say something entirely too 'thoughtful.' Something like, "Fish don't have feet so they can't really use stairs." Or, "It would be hard to use fins on steps." Or I might have posed this question for him to ponder,"How do you think the fish would get up those steps?"