The Best Water Parameters for Guppies

Guppies are one of the most popular and easy-to-care-for tropical fish, making them a favorite among both beginner and experienced aquarists. However, to truly thrive, guppies require specific water parameters, which might seem daunting to some. In this article, we’ll dive into the ideal water conditions for guppies, ensuring that these vibrant little fish can flourish in your tank.

guppy fish water parameters

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From water temperature to pH levels, and even my own experiences in creating the perfect guppy habitat, you’ll find all the essential information you need to succeed. So, let’s dive in and explore the world of guppy care!

Water Requirements for Guppies

Parameter Ideal Range for Guppies
Temperature 74°F – 82°F (23°C – 28°C)
pH 6.8 – 7.8
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate < 20 ppm
General Hardness (GH) 8 – 12 dGH
Carbonate Hardness (KH) 8 – 12 dKH

Understanding the water parameters in the table above is crucial to maintaining a healthy guppy tank. Take the time to monitor and adjust these levels as needed; the extra effort will pay off with healthy, vibrant guppies swimming happily in your aquarium.

  • Temperature: Guppies thrive in warmer waters. I usually keep my guppy tank between 76°F and 78°F, which promotes healthy growth and coloration. A reliable heater and thermometer can help you maintain a consistent temperature in your tank.
  • pH: Guppies are reasonably adaptable to different pH levels, but they do best when their environment is slightly alkaline. I make sure to test my tank’s pH regularly and use pH buffers if required to maintain the proper balance.
  • Ammonia, Nitrite, and Nitrate: These parameters are vital to monitor in any aquarium but become even more critical in a guppy tank. Ammonia and nitrite levels should always be at zero, while nitrate levels should be below 20 ppm. I find that regular water changes, using a quality filter, and not overfeeding my guppies help maintain ideal levels.
  • General Hardness (GH): Guppies thrive in moderately hard water, with a GH of 8-12 dGH. If you live in an area with soft tap water, you can use remineralizing agents to increase the GH, providing a healthy environment for your guppies.
  • Carbonate Hardness (KH): Similar to general hardness, guppies prefer a moderately high carbonate hardness of 8-12 dKH. Adequate KH levels will help maintain stable pH levels in your tank. If needed, you can use specialized buffers or supplements to adjust the KH in your aquarium.

guppy fish breeding

Best Water Parameters for Breeding Guppies

Breeding guppies is an exciting and rewarding aspect of keeping these beautiful fish. However, they tend to be more sensitive during the breeding process – making it essential to maintain optimal water conditions. By following these guidelines, you can create an ideal environment for breeding guppies, increasing the chances of successful reproduction.

Parameter Ideal Range for Breeding Guppies
Temperature 78°F – 80°F (25°C – 27°C)
pH 7.0 – 7.4
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate < 10 ppm
General Hardness (GH) 10 – 15 dGH
Carbonate Hardness (KH) 10 – 15 dKH
  • Temperature: Slightly warmer waters encourage breeding behavior in guppies. By raising the temperature to around 78°F – 80°F in the breeding tank, you create ideal conditions for courtship and spawning.
  • pH: A pH level between 7.0 and 7.4 is optimal for breeding guppies. It provides the right balance of acidity and alkalinity, promoting a healthy environment for both the parents and the developing fry.
  • Ammonia, Nitrite, and Nitrate: As with non-breeding guppies, it’s crucial to keep ammonia and nitrite levels at zero in your breeding tank. Additionally, maintaining nitrate levels below 10 ppm is essential to ensure the health of the fry.
  • General Hardness (GH): For successful breeding, aim for slightly harder water conditions than usual, at around 10-15 dGH. These levels promote healthy growth and development of guppy fry.
  • Carbonate Hardness (KH): A moderately high carbonate hardness of 10-15 dKH aids in maintaining stable pH levels in the breeding tank. Make sure to monitor and adjust KH levels as needed to support the health of your breeding guppies.

By focusing on the specific water parameters needed for breeding guppies, you can increase the chances of success and enjoy the experience of watching new life emerge in your aquarium. Happy breeding!

guppy fry

Best Water Parameters for Growing Guppy Fry

Growing guppy fry is an incredibly rewarding experience, as you watch them develop from tiny specks to colorful, lively fish. Ensuring that your fry has the best water conditions is key to their growth and survival. Here are the ideal water parameters for growing guppy fry, allowing them to thrive and reach adulthood:

Parameter Ideal Range for Guppy Fry
Temperature 78°F – 82°F (25°C – 28°C)
pH 7.0 – 7.6
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate < 10 ppm
General Hardness (GH) 10 – 15 dGH
Carbonate Hardness (KH) 10 – 15 dKH
  • Temperature: Warm water temperatures (78°F – 82°F) promote a faster metabolism in guppy fry, helping them grow more quickly. Keeping the fry’s environment at this temperature range also encourages robust immune systems, improving their overall health.
  • pH: Guppy fry tend to thrive in a pH range of 7.0 to 7.6. It’s essential to monitor and maintain this level, as fluctuations can be detrimental to their well-being.
  • Ammonia, Nitrite, and Nitrate: As with adult guppies, the ammonia and nitrite levels in a fry tank should be at zero. Nitrate levels should be kept below 10 ppm for optimal fry growth. Providing stable and clean water is key, so ensure regular water changes and testing.
  • General Hardness (GH): A GH of 10 to 15 dGH is ideal for growing guppy fry. This hardness promotes a healthy environment for the fry, supporting their development.
  • Carbonate Hardness (KH): Fry tanks require moderately high carbonate hardness levels of 10 to 15 dKH. This contributes to a stable tank environment by helping maintain consistent pH levels.

Following these water parameter guidelines for growing guppy fry will maximize their growth potential and health, giving you the satisfaction of raising strong, vibrant guppies that reach adulthood ready to grace your main tank with their enchanting presence.

guppy fish care

Keeping Stable Water Parameters for Guppies

Consistent water parameters are vital to maintaining a healthy and stress-free tank for your guppies. Fluctuations in water conditions can result in stressed, sick, or even dead guppies. I’ve learned some essential tips over the years to help maintain stable water parameters, listed below:

  • Regular Water Changes: Performing weekly water changes (roughly 20-30% of the tank volume) not only helps keep your water clean, but also stabilizes the pH, GH, KH, and nitrate levels. Make sure to treat tap water with a water conditioner to remove chlorine and chloramines.
  • Invest in a Quality Filter: A proper filtration system contributes to maintaining stable water parameters by removing waste, ammonia, and other harmful substances. I highly recommend using a filter that incorporates mechanical, biological, and chemical filtration capabilities.
  • Test Your Water: Regularly testing your water parameters is the key to maintaining a healthy tank. Use reliable aquarium test kits to monitor temperature, pH, ammonia, nitrite, nitrate, GH, and KH. Testing at least once a week helps you stay on top of any changes that might occur and take action if needed.
  • Proper Feeding: Overfeeding your guppies can lead to increased waste production and an imbalance in your tank’s water parameters. I suggest feeding your guppies small amounts once or twice a day, only providing what they can consume in a few minutes.
  • Control Algae Growth: Excessive algae growth can be detrimental to your water quality, as it can absorb important nutrients, fluctuating parameter levels. Control algae growth by reducing excess light exposure, avoiding overfeeding, and adding some live plants to absorb surplus nutrients.
  • Have a Routine Maintenance Schedule: Lastly, having a routine schedule including water changes, filter cleaning, and general tank maintenance is essential for keeping a stable, healthy aquarium environment for your guppies. Consistent care is key to maintaining stable water parameters.

By using these tips, you can maintain a stress-free and healthful environment for your guppies, allowing them to thrive and display their captivating colors and patterns in your aquarium.

Getting Rid of Ammonia, Nitrites, and Nitrates

Keeping ammonia and nitrites at 0 ppm and nitrates below 20 ppm is challenging for all fish keepers. While guppies are hardy, they are highly affected by these, especially ammonia, so you have to get rid of them. Here are a few tips to help you in this process:


Ammonia buildup in your guppy tank can lead to Ammonia Poisoning, a dangerous condition that can harm or even kill your fish. Keeping ammonia levels at zero is essential; as an aquarist, you must prioritize lowering ammonia levels to maintain a healthy environment for your guppies.

Here are some useful steps to help you tackle this issue:

  • Test Your Water: Regularly testing your water parameters is crucial for early detection. Ensure you have a reliable test kit to measure ammonia levels along with other essential water parameters.
  • Partial Water Changes: Performing partial water changes is an effective way to lower ammonia levels. Replace around 20-30% of your tank water with conditioned, dechlorinated water of the same temperature. Repeat the process until ammonia levels are back to zero.
  • Reduce Feeding: Overfeeding your guppies can lead to unnecessary waste, causing a spike in ammonia levels. Make sure to only feed your guppies small amounts once or twice daily.
  • Remove Dead Plants and Fish: Decaying materials can significantly contribute to ammonia buildup. Regularly check your aquarium for deceased fish or rotting plant matter and remove them promptly.
  • Maintain Your Filter: Your filter plays a critical role in ammonia breakdown. Ensure that your filter is working correctly, with adequate flow rate, and properly cleaned filter media.
  • Boost Biological Filtration: Strengthen your biological filtration to speed up the process of converting ammonia to safer compounds. Adding a live bacterial supplement or additional beneficial bacteria (such as from an established tank) can help establish a more robust nitrogen cycle in your aquarium.
  • Use Ammonia Absorbers: In cases of persistent high ammonia levels, you can use ammonia-absorbing products such as zeolite or activated carbon to lower ammonia levels. These can be added directly to your filter.

guppy fish red blood spots


Nitrites are another critical component of your aquarium’s water parameters that must be closely monitored, as elevated nitrite levels can be harmful to your guppies. Nitrites are converted from ammonia by helpful bacteria in a functioning nitrogen cycle, and then further broken down into nitrates. 

  • Test Your Water: Regularly test your water using reliable test kits to check nitrite levels. It’s vital to ensure that the nitrite concentration remains steady at zero ppm.
  • Monitor the Nitrogen Cycle: Ensure your tank’s nitrogen cycle is well-established and stable. Any disruptions, such as inadequate filtration or an excessive bioload, can impede the conversion of harmful nitrites to safer nitrates.
  • Partial Water Changes: Perform partial water changes (20-30%) to maintain low nitrite levels if they start to rise. A water conditioner that neutralizes ammonia and nitrite can be beneficial during this process.
  • Add More Beneficial Bacteria: If your aquarium is lacking sufficient beneficial bacteria, you might experience persistent nitrite spikes. Adding live bacteria available at local pet stores, or seeding from an established tank, can quickly improve the nitrogen cycle and help reduce nitrite levels.
  • Optimal Filtration: Use a high-quality filter with a mix of mechanical, biological, and chemical filtration to promote the breakdown of harmful substances, including nitrites.
  • Monitor Your Aquarium’s Bioload: High numbers of fish, invertebrates, or decaying matter can lead to excess waste and elevated nitrite levels. Make sure your aquarium is not overstocked or filled with an excessive amount of decaying organic materials.
  • Reduce Feeding: Overfeeding your guppies may lead to increased waste, which can contribute to elevated nitrite levels. Feeding your fish small amounts once or twice a day is optimal to avoid overloading the tank.


Nitrates are the final product of the nitrogen cycle, as beneficial bacteria break down ammonia and nitrites. Although nitrates are generally safer than their predecessors, allowing concentrations to rise too high can be harmful to your guppies.

Therefore, keeping nitrate levels in check is essential to maintaining a healthy aquarium. Below are steps you can take to prevent excessively high nitrate levels.

  • Test Your Water: Regularly test your aquarium waters for nitrates using a reliable test kit. Aim to maintain nitrate levels below 20 ppm for optimal guppy health.
  • Regular Water Changes: Consistently perform water changes of 20-30% to help control nitrate levels. Always use a water conditioner to treat the replacement water, and ensure it is the same temperature as the tank’s water.
  • Proper Filtration: Use a high-quality filter system that incorporates biological, chemical, and mechanical filtration to control nitrate levels effectively.
  • Clean Your Tank: Regularly clean your tank’s substrate and decorations, as accumulated waste can contribute to increased nitrate levels. You can use a gravel vacuum or a siphon when performing water changes to facilitate this.
  • Plant Your Aquarium: Live aquatic plants are natural nitrate absorbers, as they utilize nitrates for growth. Adding plants like java fern, Anubias, and hornwort offer a natural and aesthetically pleasing way of managing nitrate levels in your aquarium.
  • Monitor Feeding: Overfeeding your guppies can lead to excessive waste and increased nitrate levels. Stick to feeding your guppies small portions once or twice a day.
  • Check Your Source Water: Be sure to test nitrate levels in your source water as well. High nitrate levels in replacement water can contribute to elevated nitrate levels in your tank. If additional treatment is needed, consider using a nitrate-removing resin, filter, or reverse osmosis setup.


In conclusion, the key to thriving guppies lies in maintaining the best possible water parameters suited to their specific needs. By understanding and managing temperature, pH, ammonia, nitrite, nitrate, general hardness, and carbonate hardness, you create an ideal environment for your guppies to flourish.

Focusing on each stage, whether it’s breeding, raising fry, or simply ensuring your mature guppy’s well-being, will ensure success and enjoyment in your guppy-keeping journey. Remember, consistent care and regular monitoring can make all the difference, providing a vibrant and captivating aquarium for you and your guppies to enjoy.

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