I remember Dad telling me the story of when he went fishing as a boy. 

He used to love fishing, one of the days he had a particular impressive haul of fish which he decided to take back to his Granddads (GD) house which had a pond. Dad thought it would be nice idea to restock his GDs pond with his impressive haul, so he tipped them all in the pond and happily went home. 

It was a few days later that dad went round to his GD only to see him looking quite upset and confused. Dad ased him what was wrong and GD said that most his fish had been killed and there were some fish in his pond that he didn't recognise. Dad then asked if he knew what had attacked the fish to which GD replied, that somehow a Stickleback had gotten into the pond and killed his fish! Unknown to Dad his impressive haul had included a Stickleback! I believe Dad did own up to his GD about what happened.