Daughter: "When are Mr. Fishy and Mrs. Fishy coming back from the vet's?
Me: "I'm not sure. They're probably taking a vacation in the ocean! Doesn't that sound like fun?"
Note: The only trip those fish have taken was to the hereafter, via the toilet. Using the Dad-i (or Mom-i) mind trick isn't pretty, but sometimes necessary.
Note2: Yes, their names were Mr. Fishy and Mrs. Fishy.