Carps and Catfishes

In my English class we are doing a unit on mysteries, so for the start of class warm-up we do logic puzzles. Today we had to logic puzzles that I will now share.
Clarence sells fish. He enjoys playing pranks on people by switching around the signs on the fish barrel. He has three barrels, Carp, Catfish, and Catfish & Carp. If you ask, he will show a fish from one barrel. All of the signs are incorrect. There are two possible answers.
For this riddle my, truly brilliant thought process was, "Catfish and carp, carp, catfish? Think if he shows the carp in the catfish barrel... wait no.... um.... what kind of creep is the Clarence guy? You can't trust people named Clarence. Especially if they sell carp and catfish. What's with all the alliterations? Who buys Catfish or Carp? Carp is gross! So is catfish and who wants them together!? Out of a barrel? That's not sanitary. What kind sick joke is this?!....
That my friends, is thinking outside the box.
The second riddle was easy, An old man dies and leaves all of his money to one of his heirs. The two heirs will have a horse race. The owner of the loosing horse takes the money. How can you make this a competitve race?
This one actually had a simple solution that I understood. switch horses. the first heir can ride the others heirs and vice versa. that way they push themselves to win, because if their horse looses, then they will get the money. sorry if I did a bad job explaining, but it made sense to me. Of course that might not be a good thing considering how I handled the Clarence problem...