This dive site, known as the 'Haunted Mansion' at Lake Motosu, Japan, is a unique freshwater dive site centered around a massive sunken tree. Entangled algae give the submerged tree a ghostly, mansion-like appearance underwater. Located at 900m altitude, it demands special attention to buoyancy control and adherence to high-altitude diving protocols. The site is primarily known for its distinctive underwater topography, dominated by this singular, large natural structure and its eerie ambiance.
The freshwater ecosystem of Haunted Mansion is home to a variety of marine life. Divers can expect to see black bass, catfish, crocodilefish, ayu, wakasagi, carp, Japanese carp, sculpin, and threadfin bream. The site is particularly noted for its macro life, including various nudibranchs, which can be found amongst the sunken trees and aquatic plants.
The best time to visit Haunted Mansion would likely be during warmer months for more comfortable diving conditions, though specific seasonal highlights are not detailed. Divers must be prepared for high-altitude diving, which includes adjusting dive computers and tables, and exercising precise buoyancy control due to the reduced atmospheric pressure. Its relatively shallow maximum depth of 17 meters and average depth of 8 meters make it accessible and appealing for both scuba divers and freedivers seeking a unique freshwater ecosystem experience.
