High-altitude wetlands in the Himalaya are critical biodiversity rich ecosystems, supporting unique alpine flora and fauna while providing essential ecosystem services to downstream communities. However, due to their remote locations and extreme environmental conditions, these ecosystems remain understudied. This study presents a comprehensive faunal assessment of the Tembao Wetland Complex (TWC) in Sikkim, India, located at an elevation of 5,200 m asl. The study recorded five butterfly species, indicating the presence of diverse insect life adapted to high-altitude conditions. Observation of (Boulenger's Lazy Toad), reaffirmed the significance Scutiger boulengeri of TWC as a key breeding ground for high-altitude amphibians. Avian sampling revealed 16 bird species, with evidence of breeding activity in many, underscoring the wetland's role as a crucial avian habitat. Additionally, direct and indirect observations of five mammalian species highlight the area's importance for sustaining wildlife populations in these extreme conditions. Given its ecological significance, we advocate for the designation of TWC as a Ramsar and Heritage Site to ensure the long-term conservation of its biodiversity and to recognize the broader importance of high-altitude wetlands in the Himalayan landscape.