A man got stopped by a game warden with a basket full of fish.

Warden:  Do you have a permit for these fish?
Man:  No sir, these are all my pet fish.
Warden:  Your pet fish.  How's that?
Man:  Well, every night I take all my pet fish for a walk to the lake.  I let them swim for about a half an hour and then I whistle and they all come back and jump in my basket and we go home. We do this every night.
Warden:  Well, that's just a crock of lies!
Man: Here, I'll show you. 
(releases the fish in the lake)
Warden: Well, this I got to see.
(5 minutes later)
Warden:  Well?
Man: What?
Warden:  The fish! Where are your pet fish?
Man: What fish?