Aphanius apodus

Aphanius apodus, also known as the Terrestrial Killifish, is distinguished by its adaptability to extreme saline conditions, often outcompeting other species in such environments. Due to their unique adaptation, these fish are a rare find in standard aquarist setups but are a fascinating study for those interested in extreme environmental adaptations. They're relatively peaceful but essential in maintaining specific water conditions for their long-term health and wellbeing.