Transparent goldfish

In an effort to reduce the need for unnecessary laboratory dissections, researchers from Mie University and Nagoya University have succeeded in producing goldfish with transparent skin.

The see-through fish was produced by repeatedly selecting "ryukin" goldfish with pale skin and breeding them together over a period of three years. The resulting fish has scales and skin that lack pigments, offering observers a clear view of its internal organs.

According to the researchers, the transparent goldfish are expected to live up to 20 years. They could grow as long as 25 centimeters and weigh more than 2 kilograms, which is much larger than other types of fish typically used in experiments, such as zebrafish and Japanese medaka.

The fact that goldfish lay several thousand eggs at a time makes them useful subjects in experiments involving the observation of blood makeup and the operation of internal organs. Transparent zebrafish, which also lay a large number of eggs, have often been used by researchers in the laboratory, but their small size makes them ill-suited for studying blood and organs.

The researchers suggest that although pale skin may be a disadvantage for goldfish in the aquarium, it benefits science by reducing the need for dissection and providing a view of the three-dimensional position of the internal organs inside the body.