Photo/Illutration

Editor's note: This is part of a series of videos offering an up-close perspective on the animal kingdom. A special 360-degree video camera system was set up in zoos and other facilities to show how the animals view their world as they interact.

Also visit our special 360-DEGREE LIVES page (http://t.asahi.com/360lives), where you can watch all the previous videos.

* * *

Although little known outside of their native river habitats that flow into the Tokai region's Ise and Mikawa bays, “nekogigi” catfish are not only designated as a national treasure by the central government but also an endangered species.

The Gyogyo Land aquarium in Toyokawa, Aichi Prefecture, has been trying to bolster nekogigi numbers and managed to hatch 500 or so eggs this summer.

By early October, the fry had grown to about three centimeters in length and were placed into three tanks in the backyard. The fish, naturally nocturnal and cautious, hide under fake rocks or in dimly-lit areas.

“These young ones will be released in local rivers suitable for their habitat,” said staff member Atsushi Sugiura.

The catfish fry were later kept by the land ministry’s Shitara Dam Construction Office, which is working to conserve nekogigi stocks. Half of them were released in November.

Because they have a limited travel range, they are susceptible to changes in their environment caused by river improvement and coastal protection projects, heavy rain and other factors, which makes it difficult to maintain their population, Sugiura said.

It is said that nekogigi spawn once every several years. Their territorial nature is another factor behind their low rate of breeding.

Gyogyo Land succeeded last year for the first time in hatching one egg. Between June and July of this year, staff members found countless eggs attached to rocks and other surfaces.

According to Sugiura, there are four Bagridae varieties belonging to the Siluriformes order in Japan. They are called nekogigi because they have a round head and barbels resembling the whiskers of a cat (“neko” in Japanese) and make a squeaking sound "gigi" when they are caught.

They mainly feed on insect larvae, small fish, shrimp and algae. Adults grow up to about 13 cm.