What Is the Proper pH Level for Tetras?

By Rochelle Leggett

Fish are attractive and often low-maintenance pets, but most fish are somewhat delicate and have specific needs for the condition of their water. Maintaining an ideal pH level of the water in an aquarium is important for many fish, including tetras. However, tetras are fairly adaptable, and measuring and creating an ideal pH level in water for tetras is not difficult.


In biological terms, the word "tetra" refers to any member of the family characidae that also belongs to the order characiformes. There are more than 1,500 species of tetra, all living in tropical and subtropical Africa and the Americas. While many types of tetras are kept as pets, the neon tetra is the most common type. These fish are known for being non-aggressive, attractive and easy to care for. Tetras are often kept in small schools as a community fish.

Water pH

The pH of water refers to how acidic or basic it is. A neutral pH is 7. Anything below 7 is acidic and anything above 7 is basic. Rainwater ranges between a pH of 5 and 6. Freshwater tends to have a pH of 6 or 7. Seawater is basic, and tends to be around a pH of 8. Fish are have adapted to live in the pH level of their native habitat, and putting a fish in water that it has not adapted to can cause stress, sickness and possibly death.

Conditions for Tetras

Tetras are freshwater fish, but they can adapt to other water. Most tetra species thrive best in water that is neutral or slightly acidic, with a pH of between 6.5 and 7. However, they are able to withstand a pH range of 5 to 7.5 with no harmful effects. This adds to the appeal of tetras as a community fish. If you have other fish that do not tolerate a wide pH range, a tetra is able to adapt to the preferred pH of your other fish.

Maintaining pH

It is important to test the pH of tank water often. You can purchase different types of kits that make this simple. To maintain a neutral pH for tetras, you may want to add a buffer, which is a chemical that prevents water from becoming too acidic or too basic. There are chemicals that you can add to the water to change the pH as well, although adding too much at a time can harm the fish. There are also many methods of slowly changing the pH of water over time. For instance, adding decorative natural wood or filtering water over peat are both effective ways to lower water pH.