According to Mysteries at the Monument, Harry Watrous and Colonel William Mann were avid fishermen, and the two decide to see who can catch the biggest trout in the lake. When Mann showed Watrous a 40-pound whopper he had just caught, he knew he wasn't going to catch anything bigger and realized he had lost the bet. However, days later, Watrous discovers he had been pranked, Mann had ordered a fake fish, and from a distance it looked real.
As revealed in Mysteries at the Monument, Harry Watrous and Colonel William Mann were passionate fishermen, and they agreed to see who could catch the largest trout in the lake. When Mann displayed a 40-pound whopper he had just caught, he understood he wouldn't be able to catch anything bigger and admitted he had lost the wager. However, days later, Watrous found out he had been duped, Mann had ordered a fake fish, and from a distance it appeared genuine.