Photo of a transparent goldfish, December 7, 2009. (Photo: Xinhua/AFP)

A team of Japanese researchers has created transparent goldfish. The fish are 25 centimeters long and weigh 2 kilograms. They are expected to live 20 years.

"You can see a live heart and other organs because the scales and skin have no pigments," said Mie University Professor Yutaka Tamaru, one of the researchers. "You don't have to cut it open. You can see a tiny brain above the goldfish's black eyes."

Tamaru added that the fish were developed by selecting and breeding mutant goldfish with pale skin. They are expected to offer a realistic alternative to controversial classroom dissections.

Photo of a transparent goldfish, December 7, 2009. (Photo: Xinhua/AFP)