Currently there are 6 native Wideangle Fisheye Prime lenses for OM System OM-5 and 2 of these lenses are autofocus (AF) type.
OM-5 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on OM-5.
Since OM System OM-5 has environmental sealings (Weather Sealing), you may like to couple your camera with one of these 1 Wideangle Fisheye Prime lenses with Weather Sealings.