Melanotaenia ajamaruensis

**Ajamaru Lakes Rainbowfish (Melanotaenia ajamaruensis)** The Ajamaru Lakes Rainbowfish is a small freshwater fish endemic to Indonesia's Bird's Head Peninsula in West Papua. Adults typically reach 8-10 centimeters in length, displaying the characteristic elongated body shape of rainbowfish with distinctive blue-green coloration and orange-red fins. Males exhibit more vibrant colors during breeding season. These schooling fish feed primarily on small invertebrates, algae, and organic detritus, playing an important role in their aquatic ecosystem's nutrient cycling. This species exists exclusively in the Ajamaru Lakes system, a series of interconnected freshwater lakes located in the Tambrauw Regency. The lakes feature clear, slightly alkaline water with temperatures ranging from 24-28°C, surrounded by tropical rainforest that provides essential organic input to the aquatic system. The species faces critical threats from habitat degradation and potential introduction of non-native fish species. Mining activities in the region pose risks through water pollution and sedimentation. Additionally, the limited geographic range makes the entire population vulnerable to localized environmental changes or catastrophic events. Conservation efforts remain limited due to the remote location and lack of comprehensive population studies. The species has been collected for the international aquarium trade, though sustainable captive breeding programs could potentially serve as insurance populations. The current outlook remains uncertain. Without detailed population assessments or active habitat protection measures, the species' extremely restricted range continues to pose significant extinction risks. Immediate research and conservation intervention are needed to prevent potential loss of this endemic rainbowfish.