The landscape around the lake is covered with Strombolian scoria cones and trachyte domes.

[2] The Andranomena and Mariandrano rivers empty into the lake from the east.

[2] There are reedbeds along the edges of the lake, composed mostly of species of the reed Phragmites and the sedge Cyperus, which grow up to two meters high.

[3] The environment of the lake and its tributary rivers have been altered by pollution, erosion and siltation, habitat destruction, and the introduction of exotic species.

The native fish Ptychochromoides itasy, last observed in the lake in the 1970s, was thought extinct until a population was discovered in the Sakay River.