Knipowitschia milleri

**Acheron Spring Goby (Knipowitschia milleri)** The Acheron spring goby is a small freshwater fish endemic to a single spring system in northwestern Greece. This diminutive species typically measures 2-3 centimeters in length and displays the characteristic elongated body shape of gobies, with fused pelvic fins forming a sucker-like disc. The species exhibits cryptic coloration with mottled brown and gray patterns that provide camouflage among rocky substrates. As a benthic species, it feeds primarily on small invertebrates and plays a role in the aquatic food web of its highly specialized habitat. The species is found exclusively in the Acheron River spring system in the Epirus region of Greece, inhabiting cool, clear spring waters with stable temperatures year-round. This extremely limited geographic range makes it one of the most geographically restricted fish species in Europe, confined to just a few square kilometers of suitable habitat. The primary threat to the Acheron spring goby is habitat modification and degradation of its spring environment. Water extraction for agricultural and domestic use poses significant risks to the delicate hydrological balance of the spring system. Additionally, pollution from agricultural runoff and potential tourism-related impacts threaten water quality in this sensitive ecosystem. Conservation efforts remain limited due to the species' recent scientific recognition and remote location. Basic ecological research is ongoing to better understand population dynamics and habitat requirements. The species' survival depends entirely on maintaining the integrity of its single known habitat, making targeted habitat protection essential for preventing extinction. Without immediate conservation intervention, the outlook remains precarious.