Moonan

Moonan is the moon that orbits the BIONICLE Planet. It's official name isn't Moonan, but it's inhabitants call it that.

Moonan's surface is completely barren, but it's hollow inside. The inside consists of millions of domes, like inside Mata Nui's body, only there are more domes in Moonan. The domes are filled with water and there are also many caves in there. The domes are inhabited by Water Rahi, most of them big and dangerous. There are only a few species of land Rahi in Moonan, most of them in the Matoran Cave.