The island of Sangeang is located 45 kilometers east of Bima, it is a small and active volcanic island (Gunung Api) where lava ridges running down its rather steep green sides can be seen.
Clear waters and good soft, hard coral and anemone growth are present here. Most regular marine fishes can be found at this dive site along with ribbon eels, cowries and underwater spiders. The currents at Mentjeng Wall can be savage due to its exposed position but there are plenty of sheltered places to hide. It is a macro haven at the base of the wall at around 20 meters where countless nudibranchs and hariry critters can be found.
Around the ridge at Tikno's Reef and Black Magic the reef breaks up over dark brown volcanic ash and sandy patches at 18 meters, its another macro delight. One of the highlights of the island being the mimic octopus at a site called Copycat Copycat ... if you can find it in this underwater desert!
Careful observation at some spots will reveal volcanic bubbles escaping from the sea bed through air vents.
It is possible to feel the heat from the sulphur covered rocks here. Often the visibility can be washed out as larger air exchanges disturb the sediment on the sea bed.