Photo by Brian Moulton.

Call it the great carp caper of 2013: Two men posing as maintenance workers stole 400 koi fish from an office park pond in Herndon, Va.

The theft happened this month over the course of four visits to a pond near 2411 Dulles Corner Park. WNEW has more:

Employees told authorities that two men, calling themselves pond maintenance workers, said they were checking on the health of the fish. They claimed that they were removing unhealthy fish and leaving the healthy ones behind. They were seen scooping the fish with large nets and placing them into coolers between 1 p.m. and 4 p.m. on June 8, 9, 15 and 16.

Eventually employees realized that the men, described as being Caucasian and in their 50s, were not who they claimed to be and contacted police.

The Post reports that the men were also wearing sunglasses, but not phony mustaches as some of you out there may be picturing.

Depending on its size and grade, a koi fish can cost anywhere between a few bucks to hundreds of dollars.

Anyone who has seen the men or a koi fish who looks stolen should contact Det. S.D. Gaydos at the Fair Oaks Police District, (703) 591-0966 extension 5004.