Which fish can live in acidic water?

Several species of fish have adapted to live in highly acidic waters. These fish possess unique physiological adaptations that allow them to survive in environments where the pH level can be as low as 3.0 or even below. Some examples of fish that thrive in acidic waters include:

1. Amazon Hatchetfish (Carnegiella marthae): Found in the Rio Negro basin of South America, this small, peaceful fish can tolerate highly acidic conditions and is known to live in waters with a pH level as low as 3.0.

2. Killifish (Nothobranchius sp.): This group of African killifish includes several species that can endure acidic environments, making them popular among aquarists who keep specialized "blackwater" tanks that replicate acidic habitats.

3. Petitella georgiae: A small, freshwater cyprinid fish endemic to Brazil, Petitella georgiae inhabits acidic streams with pH levels between 3.0 and 4.0.

4. Bichir (Polypterus sp.): Some species of bichirs, like the Senegal bichir (P. senegalus) and Ornate bichir (P. ornate), can survive in acidic waters, showcasing their adaptability to extreme environments.

5. Rainbowfish (Melanotaenia sp.): Certain rainbowfish species, namely the dwarf neon rainbowfish (Melanotaenia praecox), can tolerate acidic conditions and are found in acidic swamp forests of Papua New Guinea.

6. Discus (Symphysodon sp.): Discus are popular aquarium fish known for their intricate patterns and vibrant colors. They thrive in soft, acidic water with a pH between 4.0 and 6.0.

7. Tetras (Some species): A few tetra species, such as the cardinal tetra (Paracheirodon axelrodi) and the ember tetra (Hyphessobrycon amandae), can adapt to acidic conditions and are common in acidic South American waters.

It's important to note that while these species are remarkable in their ability to survive in acidic conditions, their specific pH tolerance levels may vary. Creating an appropriate aquarium environment or studying the natural habitats of these species is essential to ensure their health and well-being in acidic water environments.