Koopman's Montane Voalavo is a rodent known from forested areas of Madagascar's central highlands. Its gray and ochre coat has dark tips, and its tail is long.
The 1996 description notes soft, relatively thick fur, with gray and ochre dorsal hairs tipped in dark color. The belly is dark gray, and the tail is longer than the body.
The 1996 paper describes fragmented natural forest mixed with secondary grassland near Manjakatompo at about 1,800 m. It also reports a second locality at Andringitra at about 1,625 m.
An extinction-risk assessment has not been added yet.