Are Cardinal Tetras Hardy? Can They Survive In Harsh Environment?

Cardinal Tetras are peaceful fish, but they need to be in an environment that can support them. Cardinal tetras come from the Amazon River basin, where water temperature ranges between 75-82 ̊F (23-28 ̊C). They are relatively easy to keep and need lesser care. Thus, these fish are prevalent among aquarium hobbyists. But do you think Cardinal tetras are hardy?

Cardinal tetras are hardy fish. It is because they are present in the warm, fast-moving waters of South America. These fish can survive many different water conditions and temperatures. Cardinal Tetras do not need a filter or warming up because they are hardy fish that will adapt to whatever environment you place them in.

This post will help answer those questions and discuss how you can keep your new Cardinal Tetra healthy.

What Are Hardy Fish?

Hardy fish are those fish that can quickly adapt to the temperature in our tanks. These fishes are easy-going, require minimal maintenance, and can survive in a wide range of water conditions.

Usually, these fish are the best type of fish for beginners or those busy with their lives. Some of the hardy fish that can easily survive in any tank conditions and do not require special care are

  • Zebra Danio
  • Clown Loach
  • Tiger Barb
  • Glowlight Tetra
  • Blue Neon Tetras
  • Kuhli Loach (to name a few)

Are Cardinal Tetras Hardy Fish?

Cardinal Tetras are very popular beginner fish. Cardinal tetra is the most common freshwater aquarium shooling species and is easy to keep, but they require a filter or warming up for their tropical temperature preferences.

Most owners believe that Cardinal tetras are hardy fish, but Cardinal tetras are not robust. These fish do survive well in the cold. Cardinal tetras are tropical fish and need a filter or warming up for their ideal temperature.

Cardinal tetra fish are also sensitive to changes in temperature. Thus, they need a filter or a heater to keep the tank temperature at 25°C – 26°C. Cardinal tetra fish cannot survive in cooler temperatures, especially when exposed for more than 24 hours without reaching their ideal temperature.

If you want your Cardinal Tetras to be alive and healthy, ensure that they get their optimal temperature and water conditions.

What Is The Natural Habitat Of Cardinal Tetras?

Cardinal Tetras originate from the Amazon river, where they are present in slow-moving waters. They can also live near flooded forests, so Cardinal Tetras prefer a soft substrate and plants to grow on.

In the natural habitat, Cardinal Tetras live in freshwater rich with vegetation and some areas of dense plant growth. Cardinal Tetras also prefer a pH level around neutral, but they can survive at slightly acidic or alkaline levels as well.

Besides this, these fish prefers a temperature around 77 degrees Fahrenheit (25 degrees Celsius). Cardinal Tetras will not do well if the water temperature is below 70 degrees Fahrenheit (20 degrees Celsius) and might feel threatened.

Sometimes Cardinal tetra fish are also present in blackwater rivers, where the waters contain tannins from decaying leaves and a pH of less than five due to the slightly acidic nature of these waters. However, Cardinal Tetras are familiar with these conditions but might not do well if you introduce them into a different habitat.

Do Cardinal Tetras Need A Filter Or Warming Up?

Yes, Cardinal Tetras need a filter, and they also like warmer water. In addition, Cardinal tetra is an omnivore species that can eat both plant matter and tiny microorganisms, such as zooplankton, invertebrates, or small crustaceans. Thus, they will produce more waste and need a filter to keep the aquarium clean.

Cardinal Tetra fish also prefer water that is higher in temperature than average room temperatures, so you will need an external heater as well if your tank’s ambient room temperature falls below 70 degrees Fahrenheit (21 Celsius).

Cardinal tetras are very sensitive to water conditions and do not prefer fluctuations. Although it can survive in hard water, Cardinal Tetra fish prefer neutral pH of water. Along with this, there must be regular water changes (about 20% every week), and you must maintain the tank clean.

If you could manage the water conditions without using a filter or heater, then these fish may not need it. But it is best to use them if you want your fish to be healthy.

How To Keep Cardinal Tetras Healthy?

Cardinal Tetras are an excellent fish for beginners because they can adjust reasonably well in most aquariums. In addition, Cardinal tetra is one of the hardier characin species available to tropical freshwater aquarists, making them popular among beginner hobbyists.

But still, you must be attentive towards the care of these fish if you want them to live longer. Therefore, some of the ways to keep Cardinal tetras healthy are:

Manage The Size Of The Tank/Aquarium

Cardinal Tetras can live comfortably in an aquarium size of around 20 gallons (76 liters). But larger tanks will enable you to keep more Cardinal tetra, and this will be a great advantage because Cardinal Tetras are happiest in shools of five or more.

Smaller aquariums should have few hiding places to make the fish feel safe and secure, while larger tanks can provide plenty of areas for Cardinal tetra to hide, swim and breed.

Maintain The pH Level Of Water In Your Aquarium

In general, Cardinal Tetras will thrive in water that has a pH from around 70 to 75. Cardinal tetra prefers slightly acidic conditions. They can live in brackish water if their gills are healthy without infection.

You should also know that the cardinal tetra has an organ called a labyrinth that allows them to breathe atmospheric oxygen directly from the water’s surface. Thus, Cardinal Tetras can survive in low-oxygenated waters, too.

Maintain Optimum Water Condition

Cardinal Tetras is a hardy species. They can survive in water that has a temperature from 22-28 degrees Celsius. They will not thrive in warm waters, but they do not need high temperatures to stay healthy, either.

These fish will like a little higher temperature during the breeding period, but Cardinal Tetras are usually quite adaptable. Just make sure that you do not expose them to sudden changes in temperature or pH level.

Use Lights

Cardinal Tetras do not need strong lights to thrive in the aquarium, but you should still provide them with some light. They will appreciate it if you illuminate their tank with a fluorescent tube with a color temperature of around 6000K-8000K. Cardinal Tetras will find this light source similar to the sun. They will feel more comfortable near it.

The lights will also help to avoid the algae growth on the tank walls. Cardinal Tetras are more likely to stay away from areas with less light in their tanks, so make sure that they have enough of it.

Feed Them The Correct Food

Cardinal tetra is an omnivore. They will feed primarily on insects that fall into their tanks and small crustaceans that naturally live there. However, they also eat a lot of plant material if given a chance. So you should provide Cardinal Tetras with both flake food and frozen or live bloodworms, micro-pellets as well as daphnia, which are all readily available in most pet shops.

Make Sure The Water Is Clean And Clear

Cardinal tetra can be pretty sensitive to water conditions, so it is important to maintain clean and clear water. In addition, Cardinal tetra needs a lot of oxygen. So you should consider getting an aquarium filter if you want to keep them in your tank for the long run because Cardinal Tetras like slow-moving waters or currents that resemble their natural environment.

Keep Cardinal Tetras In A Community Tank

Cardinal tetra is a schooling fish, and you should try keeping it in groups of six or more Cardinal Tetras together. Keeping this fish with other community fishes like Neon tetra, Tiger Barb, Rosy barbs, etc., can also add to the tank. You can house Cardinal tetras in a community aquarium with fishes of similar temperament and size such as rosy barbs, neon tetra, etc.

Use Plants And Decorations

It would be best to consider placing Cardinal Tetras in a tank with live plants and driftwood because this will make them feel more comfortable. Cardinal Tetra prefers well-planted tanks, and they will swim in midwater towards the top of plants. Cardinal tetras are also very active during the daytime. So you should try adding some live plants to your Cardinal tetra tank if you want them to be healthy for a long time.


How Long Do Cardinal Tetras Life?

Cardinal Tetras can live up to about five years, but that is in the wild. In an aquarium environment with conditions similar to their natural habitat, they will live for different years.

Are All Species Of Cardinal Tetras Hardy?

No, not all Cardinal Tetras are very hardy. Some of the species of Cardinal tetras that are not hardy are Red Eye Cardinal (Paracheirodon axelrodi), False Cardinal Fish (Pristella maxillaris), Neon Blue Cardinal Fish (Hyphessobrycon herbertaxelrodi), and Cardinal Tetra (Pristella riddlei).

How Do You Keep Cardinal Tetras Hardy?

It would be best if you kept your Cardinal tetra fish happy by keeping their aquarium at a comfortable room temperature, around 70 degrees Fahrenheit or 18 degrees Celsius. You should also make sure to keep Cardinal tetras in aquariums with pH levels between 4.6 to 6.2. Cardinal tetras can live in water temperatures up to 81-degrees Fahrenheit (26-degrees Celsius).

How Hardy Are Cardinal Tetras?

In terms of hardiness, Cardinal Tetras are mid-level fish. Cardinal Tetras can tolerate a range of water conditions and temperatures, given they have the suitable tank mates available for them.


In conclusion, Cardinal Tetras are very hardy fish, but they do need a filter. They can live at room temperature or higher temperatures as well. So it’s not necessary to have the tank heated up unless you want your Cardinal Tetra to be comfortable.

Moreover, Cardinal Tetras are very easy to take care of if you’re starting. You can find Cardinal tetras at most pet stores with a fish section, so they shouldn’t be too hard to find either.

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