[HIGHLIGHTS] If you put a stone from the riverbed into the aquarium... ``Marimo'' that has been reported in Japan will appear.

A man living in Kanagawa Prefecture was putting stones he had picked up on a riverbank into an aquarium where he kept tropical fish. When a marimo appeared, he investigated it at the National Museum of Nature and Science.

The research team is appealing for information as there may be other discoveries. It is the third species in Japan, following the ``Marimo'' that lives in Lake Akan in Hokkaido, and the ``Tateyama Marimo'' in Toyama Prefecture.