(A woman is purchasing a long fish called a dojo loach.)

Customer: “Now, will I need to fill the tank halfway and add some sand for it to crawl onto?”

Me: “No, ma’am, it’s a fish.”

Customer: *stares in confused silence*

Me: “Fish don’t need to crawl onto land to breathe.”

Customer: “What do you mean?”

Me: “It will be fine in a full aquarium.”

Customer: “You’d better be right!” *leaves looking dissatisfied*