The ayu, or sweetfish, is a summer delicacy in Japan. Usually coated in salt and grilled over a charcoal fire, the fish is known for its refreshingly sweet taste and is consumed widely by Japanese people every year.

While a typical specimen is similar to a small trout in appearance, an ayu with translucent scales was discovered at a fishery in Gifu prefecture late last month.

We think the issue here isn’t why this happened, but how on earth were they able to spot the little guy…

The 15 centimeter see-through ayu was found among a batch of 300,000 fish. While the scales aren’t completely transparent, you can still the general shape and color of the fish’s innards and skeleton.

The staff at the fishery are puzzled as to why the mutation occurred, pointing out that they have not once changed cultivation methods in their 40 years of operation.
According to a government research institute in Gifu, while there have been instances of goldfish or farmed killifish being born with see-through bodies due to a mutation, this is the first time on record it has been seen with ayu.

The research center kept the specimen in an aquarium for research purposes but it died at the end of the month. While the cause of death is unknown, we imagine it had something to do with the feelings of stress and isolation from being unintentionally ignored by all the other fish.

Source: Yomiuri Online , cc.rd.pref.gifu.jp

While mother nature may be responsible for the see-through ayu, Japanese scientists have been breeding their own invisi-fish for years…

▼This zebra fish was bred for cancer research

▼This goldfish was bred to stop the slaughter of innocent goldfish for science