Guppies are among those exotic fish that are very easy to care for and are very popular in the aquarium hobby, although they can also present minor issues that need to be considered to prevent problems and illness. They are extremely adaptable fish, able to live in a wide variety of water conditions. However, it's important to remember that guppies require some basic care, despite being among the hardiest aquarium fish.
Biological balance and water maintenance in the aquarium
While achieving perfect biological balance in an aquarium is impossible, this should be understood from the outset. Organic waste (food scraps, feces, plant leaves) always accumulates in a closed tank, altering water parameters. Nutrients in the form of food added to the aquarium must be considered, and to achieve balance and a healthy environment, partial water changes (typically between 20% and 30% per week) and occasional filter cleaning are necessary.
In addition to water changes, it's essential to monitor parameters such as ammonia, nitrites, and nitrates . Before introducing guppies to a new aquarium, it's advisable to complete the aquarium cycling process , which allows beneficial bacteria to establish themselves in the filter and substrate, transforming toxic waste into less harmful compounds. This process significantly reduces the risk of disease and sudden death.
Good filtration and oxygenation also help maintain stable water chemistry. A biological or sponge filter is ideal for guppies, as it provides a gentle current that won't damage their fins and offers ample support for nitrifying bacteria. Supplementing filtration with an air pump or diffuser improves gas exchange at the surface, keeping oxygen levels high.
Ideal pH, hardness and water type for guppies
Guppies can be successfully kept and bred in almost any type of water, provided the parameters remain stable. However, guppies thrive in moderately hard to highly hard water with a slightly alkaline pH.
The recommended values ​​for guppies are usually in:
- pH between 6.8 and 7.8However, many domestic specimens tolerate somewhat higher values ​​without problems as long as they are constant.
- General hardness (GH) between 10 and 30 dGHThis implies the presence of minerals such as calcium and magnesium, which are very useful for good bone and fin development.
- Temperature between 24 and 28 ºC, typical range of tropical water where the guppy's metabolism functions optimally.
Problems can occur more frequently in very soft water than in hard water, as guppies are exceptionally intolerant of sudden pH changes , which, of course, occur more rapidly in soft water than in hard water due to its low buffering capacity (KH). Therefore, the best option is to always use water of consistent quality with the same hardness and pH, avoiding sudden changes during each maintenance session.
In many homes, tap water has a pH around 8 or slightly higher and relatively high hardness. In these cases, if all the fish in the aquarium (including guppies, mollies, hardy tetras, or shrimp) are active, eating well, and reproducing, it's a sign that the high, stable pH isn't a problem . Forcing a constant drop in pH in water with high KH can be more stressful for the fish than maintaining a pH slightly above the "theoretical ideal."
How to stabilize pH and improve oxygenation
If the aquarium will be filled with soft water, it is recommended to install an air diffuser to prevent problems for the fish. This reduces the likelihood of nighttime pH fluctuations caused by carbon dioxide buildup when the lights are off and plants stop photosynthesizing.
Dissolved COâ‚‚ tends to acidify the water, and in aquariums with poor aeration, a drop in pH can occur overnight. Although this sometimes goes unnoticed, it is particularly stressful for sensitive fish like guppies. Good aeration stabilizes the pH and ensures adequate oxygen levels for all aquarium inhabitants.
If the goal is to adjust the pH safely, it's best to do so gradually. In very hard water, trying to lower the pH drastically with homemade methods (such as tea bags, peat moss, or acidic products) can be ineffective or cause continuous fluctuations. In these cases, many experienced breeders opt for reverse osmosis water mixed with tap water to achieve the desired hardness and pH, always prioritizing stability.
As for home experiments, such as using a tea bag to acidify water, these can tint the water amber and add tannins, but the actual effect on pH depends heavily on water hardness. In water with high KH, the change may be almost negligible, while in very soft water the change could be more pronounced. Therefore, any variation should be accompanied by frequent measurements with a good pH meter , and drastic changes should be avoided.
Hardiness, aquarium size and guppy population
Guppies are ideal fish for beginners and adapt perfectly to captivity. The optimal aquarium size for them is approximately 7 liters of water per adult guppy . This prevents overcrowding , facilitates maintaining stable water parameters, and reduces stress among the fish.
In medium-sized aquariums, a volume of around 40 liters is ideal for a small group of guppies, allowing for several females per male and leaving room for compatible tankmates such as peaceful tetras, corydoras, or some invertebrates. Larger tanks can accommodate a larger community, always keeping in mind the population density and the filter's capacity.
Guppies ( Poecilia reticulata ) are known for their hardiness , ease of care, and diverse colors and fin shapes. This combination of beauty and resilience makes them an excellent choice for those setting up their first aquarium, as well as for advanced hobbyists interested in selective breeding and maintaining specific color lines.
Although they tolerate moderate variations in temperature and pH, their true strength is shown when they are kept in a stable, well-filtered environment and properly fed . With good water quality control, a varied diet, and a well-sized aquarium, guppies can display vibrant colors, reproduce easily , and provide a continuous spectacle of activity in the middle and upper levels of the tank.
Understanding the ideal pH for guppy fish , the appropriate hardness, and the importance of parameter stability allows you to take full advantage of the potential of this popular species, enjoying a colorful, healthy, and long-lasting aquarium with very few problems if these basics are respected.
