What Temperature Do Cardinal Tetras Like? How To Maintain It??

Cardinal tetras are tropical fish native to the Amazon basin. They are a popular choice for beginner aquarium owners because they can tolerate a wide range of water conditions. As a result, they rarely bother tank mates, as long as you fulfill their requirements. Still, the temperature in which Cardinal tetras like to live is a matter of concern for most owners.

The temperature that Cardinal tetra likes are about 24 degrees Celsius. These fish-like temperatures are between 18 and 26 degrees Celsius, as long as the water doesn’t drop below 12 to 16 degrees celsius. Temperature is very important for Cardinal tetra survival because if they do not have a stable environment, it will cause stress on them, which can make them sick or even die.

This post will talk about the temperature Cardinal tetras like to live in and its influence on their health.

What Is The Temperature Of The Natural Habitat Of Cardinal Tetras?

Cardinal tetras originated from the soft, acidic waters of the Rio Negro drainage in Brazil. The temperature in this habitat is between 24 and 30 degrees Celsius. Temperature can vary slightly depending on the time of year, with a difference of about two degrees over twelve months.

The ideal temperature range for cardinal tetra to thrive is 25-29 C (77-84 F). However, the temperature should not fluctuate by more than a couple of degrees at night. In addition, the depth of water also affects the temperature. So, the temperature in shallow waters will be higher than in deeper areas as heat rises and dissipates into the atmosphere.

What Temperature Does Cardinal Tetras Like?

Temperature is an important factor in the fish tank. Temperature can affect your fish’s appetite, disease resistance, and color. Typically, most aquarists believe that a temperature over 86 degrees Fahrenheit or 29 degrees Celsius will cause stress to cardinal tetra, leading to death.

Thus, Cardinal tetra prefers temperatures between 76 and 82 degrees Fahrenheit (24 to 28 Celsius). Temperature fluctuation is not suitable for the fish either. The temperature should remain relatively stable to keep your fish alive and healthy.

Maximum Temperature Cardinal Tetras Can Tolerate

Cardinal tetras live in the warmer areas of South America. They can live between 55 and 86 degrees Fahrenheit (13 to 30 Celsius). Moreover, these fish cannot tolerate temperatures above 91 degrees Fahrenheit (33 Celsius).

When you keep Cardinal tetras at higher temperatures, they will not grow to their full potential and become sick.

High temperatures trigger a stress response which causes the Cardinal tetras’ immune system to lower its abilities. This makes them more susceptible to diseases that would otherwise fight off in normal water temperature conditions.

Minimum Temperature Cardinal Tetras Can Tolerate

Lower temperatures can cause the fish to grow more slowly. Temperature below 60 degrees Fahrenheit (15 Celsius) may slow down their growth rate and affect breeding and maturation.

This means that you should keep Cardinal tetra in the water temperature range between 70 and 85 degrees Fahrenheit (21 to 29 Celsius). You need a heater to keep the water warm if you live in a colder climate.

Why Is Maintenance Of Optimum Temperature Important For Cardinal Tetras?

Temperature plays a role in the physical and biological well-being of cardinal tetras. It allows them to thrive by causing chemical reactions, controlling metabolism rates, regulating their breathing rate, and enable swimming motions. In addition, it also enhances activity levels which help with hunting prey or hiding from predators.

Moreover, some of the importance of optimum temperature in Cardinal tetra are:

Temperature Affects Their Immune System

Temperature affects the immune system of Cardinal tetra. It controls their enzymes which are responsible for enhancing and also inhibiting chemical reactions. It also determines how well they can fight off diseases, infections, or parasites.

Temperature Affects Cardinal Tetras Reproductive System

Temperature impacts the reproductive system of Cardinal tetra by affecting their spawning. Usually, temperature controls the time and frequency of spawning. Thus, this will ensure the production of enough eggs for survival into adulthood.

Temperature Affects Water Quality

Temperature also affects water quality as it determines oxygen levels in the water. This can affect its pH balance which is very important while maintaining a healthy aquatic environment. So, temperature plays an essential role in the physical and biological well-being of Cardinal Tetras.

Temperature Controls The Growth Rate Of Cardinal Tetras

Temperature affects the growth rate of Cardinal Tetras. Usually, temperature determines how fast they grow and mature. A controlled temperature also helps them fight off diseases, parasites, or infections. It also allows complete life cycles, which is vital for species survival as it ensures there are enough healthy adults to repopulate the population.

Temperature Affects The Mating Behavior Of Cardinal Tetras

Temperature also affects the mating behavior of Cardinal tetras. As temperature determines how well they can reproduce, it controls their fertility and spawning rate to ensure enough adults for species survival.

Temperature Affects The Lifespan Of Cardinal Tetras

Temperature also impacts the lifespan of cardinal tetras by affecting metabolic rates, which determines age. It contributes to the aging process of Cardinal tetras as it controls their body temperature, which can either slow down or speed up natural processes.

Temperature can cause cells to age faster or slower, depending on how well they metabolize. It also influences their body’s recovery speed and ability to fight off diseases, infections, parasites, affecting longevity.

How To Know Cardinal Tetras Do Not Like The Temperature?

When Cardinal tetras do not like their tank’s temperature, they will start showing unusual behavior.

The first sign that you will notice is a visible decrease in appetite. Moreover, some of the signs that indicate Cardinal tetras do not like their temperature are:

  • lively side to side motion
  • increased respiration rate
  • increased activity
  • flared fins (if you are lucky enough to see it)
  • decrease in appetite, which might lead to less active behavior.
  • Smaller body size.

If you have Cardinal tetras, and these signs are present in your tank. It is time to check the temperature and regulate it to recover from this unusual behavior.

How To Maintain The Optimum Temperature Of Cardinal Tetras?

The optimum temperature for cardinal tetras is between 70°F and 82°F. Therefore, temperature control in the aquarium is important because if a temperature falls below or above what your cardinal tetras need, they will not develop properly and may die prematurely.

However, some of the ways to maintain an optimum temperature in the aquarium of Cardinal tetras are:

Use Heater To Control The Temperature

One of the ways to maintain an optimum temperature for your Cardinal tetras is by using a heater. Temperature control in the aquarium is important because if a temperature falls below or above what your cardinal tetras need, they will not develop properly and may die prematurely.

Use Thermometer To Monitor Temperature

If you are looking for an accurate way to monitor the temperature of your fish tank, then you must use a thermometer. You can easily monitor the temperature by using a straightforward method. Place the thermometer into your aquarium and let it sit on the bottom under any cover or rocks that may go there. This will provide good accuracy.

Install A Good Filtration System

A filtration system is essential as it helps maintain the water quality of your tank. If you don’t have a good filter, ammonia and nitrites can build up to dangerous levels, killing your fish. So make sure that you invest in a high-quality filter. 

Make sure that you install your filter correctly so it can work properly. If the water isn’t flowing through the media, there’s no pointing having a filter.

Always Use Air Conditioning

If you’re not using air conditioning for your fish tank, then it’s a good idea to get one. It will help keep the temperature in the tank stable and prevent any emergencies from happening while you are away at work or on vacation.

Air conditioners will also keep your tanks from getting too cold. If you have a room that is naturally colder than the rest of the house, it would be a good idea to put your fish tank in the stay at more stable temperatures throughout the day.

In some cases, air conditioning units might not work if you notice them hooking up to central HVAC systems. If this is the case, you should consider investing in a fish tank heater so your tanks can get to stable temperatures throughout the day.

Some FAQs

What Is The Average Lifespan Of Cardinal Tetra?

The average lifespan of cardinal tetras is three to five years. However, Cardinal tetras can live longer and healthier in an environment where their water conditions are good. 

How Many Tankmates Do Cardinal Tetras Prefer?

Cardinal tetras are not very picky when it comes to tankmates. They can live with other fish with a similar temperament but will decide on the best combination after some time in their new environment. The ideal number of tankmates is three or more.

Does Temperature Affect Cardinal Tetras?

Cardinal tetra is very sensitive to the temperature of its environment. Temperature affects them in two ways: how fast they can grow and reproduce and impacts their health if kept at higher temperatures for long periods. The ideal water temperature for cardinal tetras is between 72°F and 80°F.


In conclusion, Cardinal tetras like warm water, which is between 26°C and 28°C. If the temperature is too low or high for them, they will become sick. Temperature affects their behavior as well. If it’s too hot, then you’ll see your fish gasping at the surface of the tank because they’re having trouble breathing, and if it’s too cold, they’ll be sluggish and slow-moving.

In the end, as long as you keep your water between 26°C and 28°C, then everything should be just fine.

Thank you for reading. Keep following for more.


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