It is extremely foolish to ask advice from someone with a vested interest.
A Cormorant, whose eyesight had dimmed with age, could no longer see his prey at the bottom of the water. He devised a cunning plan to satisfy his hunger. He called out to a Gudgeon swimming near the surface of a canal, “Friend, if you care for yourself and your brethren, go and tell them that the owner of this water plans to drag it in a week.”
The Gudgeon swam away to inform the other fish of the dreadful news. They decided to send the Gudgeon back as an envoy to the Cormorant, to thank him for the warning and to seek his advice on how to escape the danger. The Cormorant, pretending to be their savior, replied, “Gather at the top of the water, and I will transport you one by one to a safe pool known only to me.”
The fish, trusting the Cormorant, followed his advice. He transported them to a shallow water, where he could easily see them and devour them one by one as he pleased.