Hepper is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Ideal pH Level for Betta Fish: Our Vet Explains

Dr. Luqman Javed, DVM (Vet)

By Dr. Luqman Javed, DVM (Vet)

PH checking solution in aquarium tank

Vet approved

Dr. Luqman Javed Photo

Written by

Dr. Luqman Javed

DVM (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

Learn more »

For new fishkeepers, one of the most daunting tasks about setting up an aquarium is figuring out if the water source they have is good for their fish. Tap water quality is usually determined by local sanitation practices and regulations set by your local sanitation department. These recommendations often try to make the water safe for people to use but they don’t factor in your fish.

Knowing if your pet is in water of an appropriate pH can be frustrating. So what do betta fish need? Fortunately, betta fish are highly adaptive to a wide range of pH values and can adjust to pH values anywhere from 5.0 to 9.0, with an ideal pH range between 6.9–7.0. Read on as we discuss the pH dynamics and the requirements of betta fish in more detail.

Hepper_divider_fish_v1-2

pH Control in Nature

pH refers to the “potential of hydrogen” and is a value assigned on a scale that determines if something is acidic, neutral, or basic. A value of 7.0 denotes neutrality. Anything lower is acidic, whereas anything higher than 7.0 is alkaline.

In nature, most freshwater ponds, streams, and lakes have a pH of anywhere between 6 to 8. Many freshwater fish kept as pets have an ideal pH range that usually falls in this range.

The pH of water in nature isn’t consistent. Rain, for example, usually has a pH of around 5.6 when it’s free of contaminants. However, rain is rarely “pure” as several factors can impact its pH.

Both natural and manufactured factors can include the following:
  • Volcano emissions
  • Lightning
  • Microbial processes that happen in the water all the time
  • Power stations and industrial power plants
  • Mining and smelting of high-sulfur ore
  • Combustion of fossil fuels

All these factors release high amounts of compounds that mix with water vapor and reduce the pH of rainwater to a value much lower than its normal amount, making it even more acidic. Fortunately, limestone found in soils in natural bodies of water counteracts this effect by buffering (increasing) the pH of water once acidic compounds lower it, helping maintain consistency.

Bodies of water where limestone isn’t present or is present in very low amounts are the most susceptible to “acid shocks”, resulting in fish death after a sudden shift in pH value after heavy rainfall periods. Fortunately, fish kept as pets are not exposed to these risks, as their pH levels can be controlled by pet keepers (if needed).

Eruption of Anak Krakatau Volcanoes Indonesia
Image Credit: Deni_Sugandi, Shutterstock

Effects of High or Low pH

Pet fish are prone to several issues in pH that are outside their acceptable range.

If the pH is lower than their ideal levels, the following issues can occur:
  • Poor reproductive performance
  • Increase in natural mucus production to counteract the acidity, which can clog the gill membranes and lead to asphyxiation
  • Long-term stress, resulting in poor growth and increased susceptibility to disease
  • At pH levels below 5, most fish perish
If the pH is higher than their ideal levels, be aware of these issues:
  • Burns on the skin, as highly alkaline water removes a fish’s mucous slime coat
  • Damages to the gills, eyes, and skin
  • Increased susceptibility to toxins (for example, ammonia is ten times more toxic at a pH of 8 than a pH of 7).

To avoid these complications, ensuring your fish are housed at a pH level appropriate for them is recommended. But where do bettas fit into all this?

Ideal pH Levels of Bettas

The absolute best pH level for bettas is 6.9–7.0. However, bettas are remarkably adaptable, and they’ve been found to be able to tolerate pH ranges from 5.0–9.0.

There are two reasons why bettas seem to display such excellent tolerance to a wide range of pH values:
  • Most fish begin to experience asphyxiation in lower pH values because the natural mucous secretions on their skin begin to clog their gills. Bettas, however, don’t seem to have this problem because they are labyrinth fish and can breathe in atmospheric oxygen from the water’s surface using their labyrinth organ.
  • Bettas seem to have endogenous factors that allow their skin to resist losing its slime coat as the pH level becomes too alkaline.

These factors afford bettas a great deal of flexibility when it comes to water pH, as most drinkable tap water has a pH value ranging from 6.5 to 8.5, according to the World Health Organization (WHO).

Multi color Siamese fighting fish Rosetail halfmoon betta fish
Image Credit: panpilai paipa,Shutterstock

Should I Check My Betta’s Water pH?

Before getting a betta, it’s a good idea to check the pH of your water source to ensure that it’s in a value that’s acceptable with your betta. If it’s in a safe range (anywhere from 5.0 – 9.0), it’s best to leave the pH as-is. Trying to consistently change the pH of your aquarium’s water is far more stressful to your fish than leaving it undisturbed.

In addition, it’s a good idea to quickly check the pH of your water source to ensure it’s relatively stable and doesn’t fluctuate much. It’s best to check the pH (alongside the ammonia, nitrite, nitrates, and other factors) of your aquarium at least once a week (ideally during a water change). If you’re in doubt about your water source, or the water’s quality, it’s best to collect some in a small container and have your aquatic veterinarian check it for you.

My Water pH Is Outside Acceptable Ranges for My Betta

If your water’s pH is outside an acceptable range for your betta, you cannot house your betta in that water.

In such a situation, you have the following options:
  • Install a neutralizing filter on your water line for a permanent solution. This is the recommended long-term solution for such a scenario. Such a filter will automatically adjust your water source to a pH of around 7.0, which is easily acceptable by the overwhelming majority of freshwater fish (including bettas).
  • Change the water source. You would have to use this new water source for every water change you perform in the future.
  • Add pH adjusters to fix the pH. This option should be considered a last resort. The pH of water should be adjusted before adding any fish into your aquarium. During water changes, the pH of replacement water should be performed before adding the water into your aquarium.
To increase the water’s pH, do one of the following:
  • Commercial pH adjusting chemicals
  • Crushed coral
  • Dolomite gravel
To decrease the water’s pH, choose one of these options:
  • Commercial pH adjusting chemicals
  • Indian almond leaves
  • Driftwood

A commercial pH adjustment product is the only quick-fix but it should never be used in an aquarium that houses fish, as the rapid change in pH (a quick increase or decrease) can stress your fish. The natural remedies are slower to produce their effect, but safer. However, their efficiency isn’t always guaranteed and they may be ineffective after a period of time.

Indian almond leaves and driftwood leach tannins into your water over time. The tannins may give your water a slightly brown tinge. This is completely safe for fish; however, it may make visualizing your fish slightly more challenging for you. Rotting leaves should be removed from aquaria. Driftwood should be washed (not boiled) before adding it into an aquarium.

sick betta fish
Image Credit: yin8003211, Pixabay

A Note About Community Fish

When housing your betta with other fish species, determining a “best” pH for your fish can be tricky, as there are so many different species of fish in an aquarium. In such a scenario, you should ensure that there is a pH range that is acceptable for all your fish, and you should only change the pH for your most sensitive fish. Most freshwater pet fish can easily adapt to pH ranges between 6.5–8.0, even if it isn’t their “ideal” pH level.

Hepper_divider_fish_v1-2

 

Conclusion

The dynamics of water pH can be truly daunting for some freshwater fish species. Fortunately, bettas are highly adaptive to a very wide range of pH values (between 5.0–9.0). For peace of mind, it’s best to install a neutralizing filter on your water source to ensure that your fish always receives water with a very safe pH readily acceptable for a plethora of different freshwater fish and invertebrates.

Other alternatives exist for modifying pH if required; however, consistently tinkering with your water’s pH can be stressful for your pet fish.

See Also:


Featured Image Credit:

Related Articles

Further Reading

Vet Articles

Latest Vet Answers

The latest veterinarians' answers to questions from our database