Cardinal Tetra Care Guide: Everything You Need to Know

The Cardinal Tetra is one of the most popular freshwater fish in the aquarium hobby. This species has a reputation for being hardy, easy-going, and peaceful. However, like all living organisms, Cardinal Tetras require proper care. The Cardinal Tetra Care Guide will help you provide your Cardinal Tetras with an appropriate environment so that they can thrive.

Cardinal Tetras thrive in soft, acidic water with a pH of 4.6-6.2, but their care requirements go well beyond that. Depending on the number of Cardinal Tetras you want to keep, you can keep them in different tanks as small as 10 gallons or more significant than 200 gallons.

Looking at the food habits, they are omnivores and will eat a wide variety of food. So, you can feed Cardinal tetras flake foods, frozen foods, freeze-dried food, and live feeders.

There is a wide range of things that you need to consider while you care for Cardinal tetra. It includes the tank setup, water chemistry, feeding them, and breeding. Hence, today we will discuss how to care for Cardinal Tetras.

Is It Necessary To Care For Cardinal Tetra?

Yes, it is necessary to care for Cardinal Tetra. There are many reasons that you would want to keep them as pets, including their beautiful colors and entertaining behavior. However, they also require the proper tank size to do well, which makes caring for them necessary.

Cardinal tetra fish originate from South America, where they live on the river’s bottom in dense vegetation. Because they are not commonly present in stores, it is vital to understand their care when choosing them as a pet.

Cardinal Tetra Care

Cardinal Tetras are a prevalent fish species in the aquarium hobby today. You can find them easily in almost any tropical fish store and online retailer. But despite how popular they’ve become, many people know little about cardinal tetra care and how to provide them with the best environment possible.

Some of the essential things to know to keep these fish happy and healthy are as follows:

  • the type of environment Cardinal tetra prefer,
  • the Cardinal tetra tank setup,
  • how to plan your cardinal tetra fish habitat.
  • what type of fish is Cardinal tetra
  • feeding schedule for Cardinal tetra fish

So, let us begin with the natural habitat of Cardinal Tetra.

Origination Of Cardinal Tetras

Cardinal Tetras originate from South America, and they inhabit the slow-moving tributaries of large rivers like Rio Negro in Brazil and Orinoco River basins in Venezuela.

The black water environment is where cardinal tetra thrives best as it simulates their natural habitat. So, Cardinal tetras prefer blackwater habitats that have very little plant life and darkly stained water and are soft and acidic.

Ideal Tank Size For Cardinal Tetra

Due to their small size, it would be best to keep Cardinal tetras in tanks between 20 and 30 gallons. They can survive well enough in smaller aquariums like 15-gallon ones, but they will be more comfortable in larger aquariums.

How Many Cardinal Tetras Should You Keep?

In general, you should only keep as many cardinal tetras as your tank can accommodate. While they are small fish and not very aggressive, they will become stressed if there is limited space to swim around or if you fail to maintain the water parameter.

Usually, you can keep as many as ten cardinal tetras in a 20-gallon tank, but you should avoid anything below five. As Cardinal tetras are schooling fish, which means they need to be in groups.

What Type Of Water Do Cardinal Tetras Prefer?

For proper care of Cardinal tetra, the water must meet specific requirements. It includes:

Water pH:

The water that Cardinal tetras live in the wild is soft and slightly acidic, with a pH level of around 4.6 to 6.2. It is best to replicate this water in the aquarium by using a substrate that will soften your tap water and have plants in your tank. These plants will help you keep the pH levels down if they get too high, which can happen when there are no plants in the tank.

Water temperature:

Cardinal tetras prefer a temperature range from 24-28 degrees Celsius. In case the temperature is below 20, you need to add some heating equipment to your aquarium. If it goes beyond 30 degrees, then there are chances that fish will die due to heatstroke or damage to their gills.

Hardness Of The Water:

Cardinal tetras prefer slightly soft water with a GH (general hardness)of under 4 degrees. The mineral concentration in water should also be deficient. For this, you can use a substrate that will soften your tap water. If you do not have access to such substrates, add peat moss directly into the tank. It will help in softening your aquarium’s water.

KH (Carbonate Hardness):

Cardinal Tetras prefer a low KH, usually under 6, to create a stable environment. However, if more than that, you can use a peat moss mixture to lower the KH.

Nitrogen Cycle In Cardinal Tetras’ Tank:

Cardinal tetras are sensitive about the nitrogen cycle in their tank, so it is crucial to maintain it. The Nitrogen Cycle consists of the transformation of ammonia into nitrite and then into nitrate. You can easily remove these compounds from your tank through water changes or a protein skimmer that you have in your aquarium.

How To Set Up A Tank For Cardinal Tetra?

The key to keeping Cardinal tetras healthy, happy and satisfied is making sure that you set your tank appropriately. The things to consider while you are setting up your tank are:

Frequently Change The Water:

Like most fish, cardinal tetra care involves regular water changes. The recommended schedule is 20 percent every two weeks or 25 percent weekly established tank with a good population of beneficial bacteria. Calculate the volume of your tank and change water accordingly.

Don’t Overstock The Tank:

Cardinal tetra fish are schooling fish, so try to maintain a minimum number of five cardinal tetras per gallon for an average-sized aquarium. Keeping them with other small Tetra species is okay, but avoid keeping more than five of a kind.

Use A Good Filter:

Cardinal tetra fish need oxygen-rich water to thrive, so make sure that there is sufficient filtration capacity in the tank. Consult with your aquarium store owner for advice on choosing an appropriate filter depending upon the type of setup you have and its capacity.

Don’t Mix Your Cardinal Tetra With Other Fish:

Cardinal tetras are very peaceful. So, they are more likely to feel harassed by other fish. Never keep them with aggressive or large predatory tankmates as they may become a meal for the predators. Also, try to avoid keeping them in an aquarium that houses cichlids, barbs, loaches, and other fast-swimming fish.

The best tankmates for Cardinal tetras are Glowlight tetras, Ember tetras, Neon tetras, and Diamond tetras.

Use Heater In Winter:

Cardinal tetra fish are native to South America, where the temperature can be pretty high. In the winter season, or if you live in a cold place, installing a heater in your aquarium(or tank) is best. If your tank does not have a built-in heater, use a submersible one instead of an external one.

Place Some Live Plants:

Cardinal tetra fish are not very fussy about their living conditions, but adding live plants in your tank is still a good idea. It will make the environment more natural and healthy for them. You can also add driftwood or pebbles to give it an authentic look.

Use Proper Substrate:

It would be best if you covered the substrate or the bottom of your tank with tiny pebbles, sand, or gravel. It usually depends upon what one is available at a pet store near you. Just make sure that the substrate is free from any chemicals that could kill your fish.

Don’t Forget To Install Lights:

You may use any light in your tank that is available at the pet store, depending upon its compatibility with live plants and fish. For example, if you have a dimly lit aquarium, then white or blue LED lights will be perfect, whereas an aquatic plant tank would require fluorescent lighting strips for adequate growth of algae and other organisms.

Cardinal Tetra Diet: What Do They Eat?

Cardinal tetra is an omnivore which means they eat both plants and animals. Therefore, they need a mix of different types of food for proper nutrition, including plant-based foods like algae wafers or Spirulina flake and meatier fare such as bloodworms.

What Should You Feed Your Cardinal Tetras?

The most common food for cardinal tetras is live or frozen brine shrimp. You can feed them high-quality flake foods, but make sure to supplement it with some live feed like bloodworms, daphnia, and tubifex worms once in a while.

How Often Should You Feed Cardinal Tetras?

Feeding cardinal tetra once a day is usually more than enough. However, if you have only a few of them in the tank, feeding them three times a week will be fine as well. You can also feed them more often if you have a larger school of cardinal tetras.

How Much Should You Feed Cardinal Tetras?

Feed cardinal tetra as much food as they can eat within a minute. Remember that you should not remove any uneaten foods until the next feeding time because they pollute your tank water and lead to other problems.

What Should You Know About Breeding Cardinal Tetras?

Breeding cardinals can be complex because they are not easy to breed in captivity, and when you do manage it, there is usually a meager success rate. The best bet for breeding these fish is to purchase two groups of cardinal tetra and put them into a separate tank without any other fish present.

Then, when they are breeding, you can add the eggs to another aquarium with fast-moving water for better chances of survival. The parents will chase the fry for a while, but eventually, they will let them go. Also, make sure to provide plenty of hiding places to avoid cannibalism during this period.

What Is The Gestational Period For Cardinal Tetras?

The gestation period for this species of fish is about three to four weeks. Their eggs are tiny and can lay between 100-300 in a single day with an average of around 200. To put that into perspective, the average size cardinals you find in stores will be around half a cm long when they hatch.

What Is The Ideal Breeding Temperature And Time Of Year?

To breed cardinals, you need to provide them with a 26-30 degrees Celsius temperature in the water. Additionally, it is best for breeding purposes if this occurs during spring or summer when they are most active. You will notice that male fish become very territorial during this time and actively chase each other around while trying to court females.

What Are The Differences Between Male And Female Cardinal Tetras?

The easiest way to tell the difference between males and females is by looking at their anal fin, which has a small black spot near it for males but not females. Females will also be more extensive than males in most cases because they are responsible for carrying the eggs.

How Long Will Cardinal Tetra Stay With You?

Once you purchase these fish, they will live for about three to five years. Usually, the average life expectancy is closer to five years. But this will depend on water conditions and other factors that may affect their quality of life.

What Are The Cardinal Tetra Disease And Illness Signs?

Unfortunately, cardinal tetras are very sensitive to changes in water conditions and temperature, leading them to develop diseases or illnesses quickly if not cared for properly.

Some common signs of this include lethargy, clamped fins, lack of interest in food, red streaking, and pale-looking gills. If your cardinal tetras display these signs, you should consult a veterinarian to diagnose the problem before taking action yourself properly.

What Are Some Of The Cardinal Tetra Diseases?

Just like every other fish, cardinals can get sick. Some diseases common in Cardinal Tetras include fin rot, ichthyophthirius (Ick), and velvet.

How Do I Prevent My Cardinal Tetra From Getting Sick?

Because they are so sensitive to water conditions, keeping them happy starts with you! You need to be able to test your aquarium’s pH levels weekly and perform a 50% water change every other week. Not only will this help prevent disease, but it also keeps your cardinal tetras happy and healthy too.

Some FAQs

Where Can You Buy Cardinal Tetra?

You can find cardinal tetras at any tropical fish store and most online retailers that sell a variety of aquarium supplies. While it may be easier to buy them through an actual shop where you can see the size and health of the fish before purchase, you can also find them online for sale.

How Much Do Cardinal Tetras Cost?

Depending on the size of fish you purchase, cardinal tetra price can range from $.05 to few dollars per fish. However, they usually cost between two and four dollars each which is not too expensive at all.

What Is The Ideal Size Of Cardinal Tetras?

When purchasing cardinal tetras, it is vital to make sure you get a healthy couple of fish. Cardinal tetras should be about two inches in size and display all the coloration of an adult cardinal, including their stunning red coloring.


Overall, the cardinal tetra is a beautiful and easy to care for fish that makes an excellent addition to any community aquarium. So if you are looking for a breathtaking fish that is hard to beat, give the Cardinal tetra a try.

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