The goldfish serve as figurative canaries to test the purity of the water supply.
Six goldfish will be used to detect water-borne contaminants at the G20 summit in Seoul.
Animal rights advocates are crying foul about the use of goldfish in this capacity.
In addition to thousands of heavily-armed police and troops, six goldfish will put their lives on the line to safeguard world leaders at this week's G20 summit in the South Korean capital.
The Convention and Exhibition Center in southern Seoul which is hosting the event will use the fish to check the purity of the water supply to restrooms, said one official.
Oh Su-Young, PR manager at the center, added that they were just part of the inspection process.
Animal rights activists criticized South Korea for placing goldfish in harm's way as part of elaborate security measures for the summit.
People for the Ethical Treatment of Animals (PETA) claimed that goldfish suffer pain in much the same way as dogs and cats..
"Protecting world leaders is very serious, but so is protecting animals who feel pain just as people do," said PETA's executive vice president, Tracy Reiman.
"There are a variety of modern scientific methods that would better protect world leaders and keep fish from enduring agonizing deaths from contaminated water," she wrote in a letter to South Korean authorities.
Oh Su-Young of the convention center earlier told AFP that the fish "symbolize an eco-friendly water policy" with used water recycled for the restrooms.
The center, which shares its water supply with a neighboring shopping mall and trade center, recycles nearly 150,000 tons of water a year at an annual saving of 360 million won ($322,436).