"River Disappears Beneath Sudden Swarm of Fish"... Citizens Stunned

School of Fish Spotted in Osaka's Dotonbori River
Swim in Dense Groups, Filling the Surface of the Water
Expert: "Most Likely Mullet Searching for Food Along the Current"

A mysterious school of fish has been spotted in the Dotonbori River, one of Osaka's most famous tourist attractions.

According to Japanese media outlets such as Yomiuri TV on December 24, the school of fish was first observed in the area on December 18. At that time, the fish suddenly appeared and swam in such dense groups that they filled the surface of the Dotonbori River. Tourists and citizens walking along the riverbank were so surprised by the unexpected sight that they stopped in their tracks and stared at the river. A local resident reported, "The school of fish suddenly appeared around 6 to 7 a.m."

A mysterious school of fish recently appeared in the Dotonbori River. Screenshot from social media platform X.

The footage capturing this scene quickly spread through social media platforms such as X (formerly Twitter). Dotonbori, well known for the Glico signboard, is a bustling downtown area in central Osaka packed with shops and is also a popular destination for Korean tourists. The video vividly shows the fish packed so tightly that the river water is barely visible.

Online users who saw the footage expressed concerns that the sudden appearance of the mysterious school of fish "could be a precursor to a major earthquake." The recent series of strong earthquakes in Japan has further heightened these anxieties. One user commented, "There was also a case where a school of fish appeared in the river during the 1995 Hanshin earthquake."

Experts say it is difficult to pinpoint the cause, but believe it is most likely a natural phenomenon. Akiko Matsui, a fish expert at the Osaka Museum of Natural History, explained, "The school of fish found in the Dotonbori River is most likely mullet that came in search of food following the current," adding, "Mullet are sensitive to changes in water temperature and may have moved to the relatively warm Dotonbori River." However, she also noted that it is "difficult to determine" the exact reason why so many fish gathered at once.

Meanwhile, in Japan, fears of a major earthquake have been growing since a magnitude 7.5 earthquake struck off the coast of Aomori Prefecture in Honshu on December 8. After the quake, the Japan Meteorological Agency issued a "subsequent earthquake advisory" for the Aomori region. This advisory, introduced in December 2022, is issued when a magnitude 7 or higher earthquake occurs and there is a high likelihood of another large earthquake within a week.