What Is An Acidophile?

An acidophile is an organism that thrives in acidic conditions. Scientifically speaking, these organisms live in a pH of 2.0 or below. Though some sources state 3.0 or even 4.0, so there may not be a formal definition of what pH level constitutes an organism as such. Substances with this pH level include vinegar and lemon juice (2.0), gastric acid (1.0), and battery acid (0.)

Normally, high acid levels destroy cells, but acidophiles have evolved mechanisms to maintain their internal pH at a constant level to prevent cell destruction. They live around the world from underground mines to national parks and been found in some of the most corrosive places on Earth. Usually, these organisms die if they live in areas that aren’t highly acidic.

In fish keeping, many acidic-loving fish are referred to as acidophiles and, while it’s a generally accepted term, they’re not true acidophiles in the scientific sense. Most of the fish that get this label live somewhere in the range of 6.0 or below. But, again, there’s no hard and fast pH rule. There are, however, a few exceptional fish that live in the Rio Negro in the Amazon that regularly experience pH drops into the 3.5 range. Similarly, fish that live in peat swamps frequently experience pH ranges from 2.0 – 4.0.