Young fishman and old fishman joke

A young man and an old man were fishing on a pier.The young man started telling the old one that the night before he caught a trout that was over 3 1/2 foot long.

The old man replied, "Oh yea, well I was here 2 nights ago and I hooked something huge. After a 30 minute fight I finaly got it up and it was an old lantern and the thing was still lit."

The young man said, "You are lying. I can't believe that."

Then the old man said, "I'll tell you what, you knock a couple of foot off your trout and I'll blow out my lantern."