How to Maintain Ideal Guppy pH Levels (Easily)

Last Updated on 2024-06-12

To provide Guppies with a substantial living space, you need to mimic their natural habitat. That’s where maintaining a proper guppy pH level in the tank will come in handy.  

The closer their water is to the necessary pH levels, the easier it will be for the guppy to thrive. So, in this article, you’ll learn everything you need to know about maintaining the proper pH levels when taking care of guppies and more! So, keep reading!

Key Takeaways:

  • Guppies thrive in water with pH levels between 6.8-7.8, but they can survive in slightly more alkaline water.
  • Maintaining a stable Guppy pH level is crucial for the health of guppies.
  • Both low and high pH levels can adversely affect guppies, causing stress, immune system weakening, and even death.
  • Regular testing of pH levels using a testing kit, such as the API Master Test kit, is recommended.
  • Testing pH levels should be done once every one or two weeks, especially after adding new decorations to the tank.

What Is The Ideal pH Level For Guppies? 

Guppies thrive in water levels between 6.8-7.8, however they can survive in slightly more alkaline water than this. And remember, while the pH level is important, keeping the pH level stable is even more important for the health of your guppy.

Why Do I Need to Maintain Guppy pH Levels in the Tank? 

Guppies are quick to adapt to any environmental changes. But, for them to really be comfortable, they need to feel at home. However, as much as they could cope with the wide range of pH levels, they too have their limits.  

Eventually, the constant pH fluctuations and uncomfortable living areas will create an unhealthy environment for guppies, which will drastically impact their basic bodily functions. That’s exactly where the ideal guppy pH level comes into play.  

So Does Ph Level Affect Guppies?

The pH level in your tank can affect guppies. If the pH level is too low or too high, it can cause stress, weaken the immune system, and even lead to death. 

Low pH levels can cause skin and fin damage, while high pH levels can cause damage to the gills, poor growth, and development, loss of appetite, and weakened immune system.

Therefore, it is crucial to regularly test and maintain the pH level within the recommended range to ensure the health and wellbeing of guppies in their aquarium environment.

guppy fish

How Do I Test the pH Levels? 

To ensure your aquarium has the necessary pH level a guppy needs it’s vital to test the water. For that, you will need a pH testing kit, which is available for purchase at almost every pet store or Amazon. There are plenty of different options to choose from, but for best results I’d definitely recommend the API Master Test kit.

When Should I Test the pH Levels? 

You should test the pH levels in your guppies tank once every one or two weeks. (Two weeks when the tank is more established.)

Tip: If you plan to decorate the tank with additional plants or objects, check the pH level in the tank after you’ve added them to make sure the water is still suitable for your guppies.  

Decorations like driftwood and Indian Almond Leaves are known to make the water more acidic, whereas crushed coral can make it more alkaline!

What Happens If The pH Level Is Too High? 

Guppies don’t mind high pH levels. But, if the levels are exceedingly over the top, they will start to affect the water chemistry. High pH levels create an unfavorable alkaline environment. The longer the guppies remain exposed to the alkalinity, the more health problems they are going to develop. 

Eventually, the water will deteriorate their mucus or protective skin layer and expose them to potential infection and bacteria. Over time, the bacteria will penetrate the system and develop into a disease, which could reduce their possibility of survival.  

What Could Be Causing the pH Levels to Spike? 

Two factors can cause the levels to spike, the first one being chemicals and the second one gas exchange. If you’re not changing the water in your tank regularly then chemicals and pollutants will build up over time.

The gas exchange, on the other hand, happens when CO2 naturally builds up in your tank. Unfortunately, the more CO2 in your tank, the more the water will become acidic over time.

What Happens if The pH Level Is Too Low? 

A guppy will not die from too low pH levels (unless they are extreme), but it can shorten their lifespan. Simply put, this species can handle bad water; however, it won’t live a long and happy life. The more the pH level drops in your guppies tank, the more acidic the water becomes, eventually damaging them.

And the more damage your guppy sustains, the more likely it is they will succumb to illness and death.

What Could Be Causing the pH Levels to Drop? 

There are a few things that can cause a drop in pH in your tank. Such as:

Ammonia Build-up

When you don’t pay enough attention to the tank (you don’t clean it, replace the water, etc), ammonia will build up. The longer the aquarium remains dirty, the more ammonia will rise, which in turn causes the pH to begin to lower

Acidic Tap Water

Another factor could be new water you are trying to add to the tank. If you haven’t tested the pH level of the water you’re using, you may find it’s more acidic than the tank


Decorations such as Indian Almond Leaves and Driftwood also release tannins into the water which make it more acidic overtime.

How To Raise The Guppy pH Level In An Aquarium?

Aerating DecorationsUse aerating ornaments like air stones, pumps, and devices. They produce bubbles, enabling solid air circulation to stabilize pH levels.
Boil the DécorUncleaned décor, like driftwood and Indian almond leaves, can release tannic acids, disrupting pH. Boil ornaments when cleaning the tank to remove lingering bacteria.
Invest in MacroalgaeMacroalgae mimic the guppy’s natural habitat, increasing pH levels and providing a cool hiding space. Requires occasional cutting to avoid overgrowth.
Replace Water More RegularlyIf pH levels drop too much, replace water frequently. Leftover food and excrement release pollutants, reducing pH. Be cautious not to shock fish during water replacement.
Dolomite ChipsDolomite chips, rich in calcium and magnesium, can increase guppy pH levels. Provides a comfortable surface and aesthetic appeal.

When looking for Guppy pH boosting tactics, one thing is vital, and you need to avoid any chemical treatments that might hurt the fish where you can. So, choose something that seems more appropriate and emphasizes the natural aesthetics of the aquarium.  

For your guppies to live long and healthy lives, you need to raise the pH level when it drops too low. Here is how you can make that happen.  

Add Some Aerating Decorations 

Aerating ornaments are not just for looks. They produce bubbles, which enable a solid circulation of air that stabilizes the pH levels. Even though they can take a lot of space, decorations like air stones, pumps, and devices can make for a useful item for managing the guppy pH level.  

(Find out more about adding air bubblers to the tank.)

Boil the Décor Before You Add It to the Water Tank 

Uncleaned décor (driftwood and Indian almond leaves) can release tannic acids, which can throw the pH level out of balance. To avoid this problem, simply boil all the ornaments when cleaning the tank to remove any lingering bacteria that have built over time. The more often you practice this tactic, the less likely you are going to expose the fish to acidic pH as well as bacteria.  

Invest in Macroalgae 

Macroalgae form a natural seabed that perfectly mimics the guppy’s natural habitat. It’s a more practical and efficient algae choice since it can increase the pH levels and provide the fish with a cool hiding space. They don’t require much maintenance, but you should cut them from time to time to avoid overgrowth.  

Replace the Water More Regularly 

If the pH level in your guppies tank is dropping too much, you may want to replace the water more frequently. All the leftover food and excrement will release pollutants into the water and reduce the pH levels. A routine clean-up can quickly solve the problem. But, be careful not to shock the fish when replacing the water.  

Try Dolomite Chips 

Most people use Dolomite chips for looks, but they can do more than that. These chips increase the guppy pH level and provide a comfortable surface. They are rich in calcium and magnesium, which will definitely come in handy when creating the ultimate environment for guppies.  

Check out this video by Guppy Channel on the best pH level for your Guppy!

How To Lower The Guppy pH Level In The Tank? 

Plenty of pH level-balancing tricks exist. For guppies to live their lives to the fullest, you need relatively normal pH levels and a comfortable environment. The interesting thing is that you don’t have to rely on chemicals to get the ideal guppy pH level. All you have to do is try any of these tactics to make it work. 

Decorate the Tank with Catappa Leaves 

If the pH level is too high, opt for some catappa leaves. These plants naturally release tannins into the water once they get submerged. Even though they taint the water with yellow color, they reduce the guppy pH level and provide a cozy living space. But, most importantly, they have anti-fungal and anti-bacterial properties.  

Prepare Some Driftwood 

To avoid exposing the guppies to toxins or harmful compounds, you should pick a natural object for dropping the pH levels. That’s where driftwood can come in handy. It has similar properties to the catappa leaves and is efficient in the short run.  

But don’t forget to soak it before you add it to the tank.  

Include Substrate or Rocks in the Tank 

Rocks are another great way to lower the pH level in your guppies tank as most of them are formed with carbonate. When this dissolves in your tank it will slowly lower the pH levels!

On top of this, rocks also provide a comfortable living space, which is great if you plan to copy the natural habitat if your guppy. So, make sure to add a bunch of flat-surface rocks without pointy edges to stabilize the guppy pH level. There is plenty of space to get creative.   

guppy in aquarium


Here are some frequently asked questions people have about the pH levels their guppies need!

What Are The Best Water Parameters For Guppy Fish?

The best water parameters for guppy fish are a water temperature between 75°F and 82°F (24°C to 28°C), a slightly alkaline pH range of 6.8-7.8, a moderately hard water with a hardness level between 8 to 12 dKH, and ammonia and nitrite levels at zero.

Can Guppies Live In 8.0pH?

Guppies can live at a pH level of 8.0. Guppies prefer a slightly alkaline pH range of 6.8-7.8 and a pH level of 8.0 falls just outside this. As long as the water pH stays constant, the guppies will be fine.

Can Guppies Live In A pH Of 5.5?

Guppies cannot live at a pH level of 5.5. This is too acidic to guppies and can be harmful for them. A pH level this low can lead to health problems, such as skin and fin damage, and even death.


Maintaining adequate pH levels for your guppies will ensure they have a healthy and happy living space. Even though keeping the pH at optimum levels can become tricky, it’s still possible to overcome these difficulties with all the methods above you can try!

As long as you experiment with your options, you will always figure out the best approach that will complement your guppy’s environment—making some simple tweaks to your tank cleaning routine to achieve that.  

You may also be interested in the ideal pH levels for plecos, gouramis, mollies, angelfish, cory catfish, and cardinal tetras too!


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