Cardinal Tetra (Paracheirodon Axelrodi): Ultimate Care Guide


Common NameCardinal Tetra
Scientific NameParacheirodon Axelrodi
OriginSouth America
Temperature73-81° F
Water pH5.0-7.5
Adult Size1.25-2 inches
DietOmnivores

Cardinal Tetra Facts

  • Cardinal Tetras can be found in the Orinoco River to the Rio Negro tributary of the Amazon River. They have also been found in the wild as far west as western Columbia. Other locations have reported schools of Cardinal Tetra in their areas, but these are most likely fish that have been released into the wild.
  • Cardinal Tetras are schooling fish that prefer to live in large groups. In the wild, Cardinal Tetra schools can number in the thousands.
  • Cardinal Tetras are not considered easy to breed in captivity, and therefore, most of the Cardinal Tetras that you see for sale are wild caught.

Identification and Markings

Cardinal Tetras are a small, brightly adorned fish. They are often chosen for aquariums for their active nature, and flashy colors. They are an easy fish to keep, and with their small size they don’t require as much room as other species.

Cardinal Tetras have silvery, metallic bodies with vibrant red bellies. These colors divide the fish laterally with a line of bright, neon blue that runs through the middle. They have transparent fins, and large eyes in comparison to their much smaller mouths.

Cardinal Tetra (Paracheirodon Axelrodi)
Cardinal Tetra (Paracheirodon Axelrodi)

Cardinal Tetra Care

Cardinal Tetras are considered hardy, and are not difficult to keep happy for even beginners to the aquarium hobby. The most important thing for Cardinal Tetra health and happiness is clean water, and the correct water parameters. If their needs are being met, then Cardinal Tetras will thrive in the home aquarium.

Food & Diet

In the wild, Cardinal Tetras can be found eating worms and small crustaceans. They are opportunistic feeders who will also eat plant matter. In captivity, they will readily eat dried or flaked foods with the occasional meaty snack. Cardinal Tetras should be fed twice per day, and only enough food that they can completely consume in about 2 minutes. This will help cut down on waste in your aquarium which in turn helps keep the water cleaner. It is easy to over feed Cardinal Tetra, so care should be taken when establishing meal times.

Size & Lifespan

At full maturity, you can expect your Cardinal Tetras to reach about 1.25 inches in length. In the wild, Cardinal Tetras can reach slightly larger and some will max out their adult length at around 2 inches.  If properly cared for you can expect your Cardinal Tetras to live anywhere from 2 to 5 years. Their lifespan is greatly determined by how well they are kept.

Cardinal Tetra Tank Size, Temperature, and pH

Cardinal Tetras require a minimum of a 20 gallon tank. It has been said that Cardinal Tetras will do fine in a smaller tank of around 10 gallons, but Cardinal Tetras are schooling fish that prefer to live in large groups. In the wild, Cardinal Tetra schools can reach in the thousands. The preferred water temperature of the Cardinal Tetra is 71F to 83F, and you will need to invest in a quality heater. It is important to also monitor the kH of a Cardinal Tetra tank. It needs to remain at a level of 2 – 6 kH. This will help neutralize acids, and prevent the pH of the aquarium from changing too rapidly which can cause issues for your fish. The pH of a Cardinal Tetra should be around 5.0 to 7.5.

Cardinal Tetra Tank Setup

When setting up a tank for Cardinal Tetras, you will want to first take a look at their natural habitat. Cardinal Tetras will do best when being kept in an aquarium that closely mimics the environment that they can be found in the wild. Sandy or muddy substrates make for the perfect aquarium floor to also grow many live plants.

Cardinal Tetras appreciate a heavily planted aquarium. A few great plants for a Cardinal Tetra tank include Amazon Sword, Java Fern, and Anubias Plants as these plants prefer the same water parameters as the Cardinal Tetra. Floating plants also make for a great addition to the ones planted. Both types of plants help keep the light levels to their lowered preferred levels. Rocks, driftwood, and leaves are all great, natural additions that can be added to the Cardinal Tetra tank. They provide natural hiding places for stressed out Cardinal Tetras.

When choosing decor, don’t forget to leave them as much open swimming space as possible. Cardinal Tetras are an active species that enjoy schooling together in large groups, and with enough room you will be able to see their unique behaviors happily displayed by the fish. 

Cardinal Tetra Breeding

Unfortunately, it is not easy to tell male and female Cardinal Tetras apart. It is said that you can more easily tell the females from the males by their more rounded bellies. This is most likely due to the female being full of eggs as she nears spawning time. If you are looking to breed Cardinal Tetras, it is better to purchase a group of juveniles and let them mature together and pair off for spawning, or purchase an already mated pair. It is also said that the anal fin of Cardinal Tetra males is more pointed than the females, but this becomes more apparent as they mature.

How Do You Breed Cardinal Tetra?

If you are looking to breed Cardinal Tetra, you will have the most success if you set up a dedicated breeding tank. It is not an easy task to get Cardinal Tetras to breed in captivity, and therefore, most of the Cardinal Tetras that you see for sale are wild caught. With a dedicated breeding tank, you will be able to replicate the correct water parameters that help trigger spawning. They prefer softer waters to spawn. If you have not noticed any spawning behaviors after placing your mature Cardinal Tetras in their breeding tank, then you will want to adjust the water parameters. This is the most difficult part of breeding Cardinal Tetras.

Cardinal Tetras will spawn at night, and this will last long into the night, sometimes until just before morning. When Cardinal Tetra females spawn, they release around 130 to 500 eggs. The eggs are very small, but it is important to remove the parent fish once you see them as they provide no parental care, and they could possibly cannibalize their young.

Cardinal Tetra (Paracheirodon Axelrodi)

Cardinal Tetra Disease

Cardinal Tetras are susceptible to many of the same ailments as other freshwater fish. They can also get Neon Tetra Disease. Neon Tetra Disease is a degenerative condition that is caused by parasites. These parasites are fast spreading and oftentimes fatal to the fish. If you suspect that your fish is affected by Neon Tetra Disease, then you will want to remove them from your tank immediately and quarantine them as it is highly contagious to other species of fish as well.

Since most Cardinal Tetras being sold in the aquarium trade are wild caught, it is important to quarantine your fish before you introduce them into your home aquarium. This will prevent you from spreading disease to your other aquarium fish.

Cardinal Tetra Tank Mates

Cardinal Tetras are a schooling species, and they prefer to live in large groups. In the wild, Cardinal Tetra schools can number in the thousands. In captivity, Cardinal Tetras are happy when kept in a small grouping of at least 6 fish in a 20 gallon tank, but if you have room for it, they would happily accept more. A larger aquarium will allow you to keep more Cardinal Tetras together in a much larger school. Keeping a single Cardinal Tetra on its own will stress out the fish, and it will be prone to sickness.

Are Cardinal Tetra A Schooling Fish?

Cardinal Tetra are small schooling fish that are often referred to as a microschooler. They prefer to live in as large a grouping as possible. These large groups give Cardinal Tetras a sense of security, and they are more likely to display their interesting social behaviors the more fish are in their school. It is recommended that Cardinal Tetras be kept in a group of at least 6 to keep them happy and comfortable.

Are Cardinal Tetras Aggressive?

Cardinal Tetras are considered a peaceful species that is usually good for community tank setups with similar behaved species. They can, however, become aggressive if they are kept in too small of a space. The more tetras you keep in a small space, the more aggressive their behaviors will become during spawning time, or feeding time. It is important to provide Cardinal Tetras with lots of room to school, and even hide to destress.

Compatible and Incompatible Tank Mates for Cardinal Tetras

Due to the peaceful nature of the Cardinal Tetra, they are able to be housed with a wide variety of species of fish in a community tank setup as long as there is enough room for each species. Cardinal Tetras make great tank mates for gouramis, other species of Tetra, Betta fish, guppies, rasboras, and mollies.

Since Cardinal Tetras are a smaller fish, they do not do well with larger, more aggressive and predatory species. Do not put Cardinal Tetras in a tank with any fish that will potentially eat fish of their size. As a general rule, if the tank mate has a mouth big enough to swallow the Cardinal Tetra, then they are not the ideal tank mate.

When introducing new fish into a community setup, it is important to observe the behaviors of the fish for a while. This will give you a good idea if the fish are able to be housed together or not. It is always possible that even though all their needs are met, that some fish will just not get along with one another, and there could be problems.

Cardinal Tetra and Betta

Cardinal Tetras make for excellent tank mates for Bettas. Both species enjoy the same water parameters, tank requirements, and even share similar dietary needs. You will run into issues if you are not keeping these species in the appropriate sized tank. Betta fish are territorial, and will potentially chase Cardinal Tetras away, but they are slow moving, and should not be able to harm them. Even though you will not see your Bettas and Cardinal Tetras fighting with one another, these two species could still cause one another stress. Stress in fish is a small issue at first that evolves into a much larger issue quickly. Stress can cause illness and disease to your fish.

Cardinal Tetra and Angelfish

It is possible to keep Cardinal Tetras with Angelfish if they are fully grown. Adult Cardinal Tetras could still become a meal for a hungry Angelfish as it is a smaller fish and the Angelfish is predatory. You will have success in keeping the two species together as long as there is adequate room, and both of the species dietary needs are being met.

Cardinal Tetra and Cherry Shrimp

The properly planted Cardinal Tetra tank can also house Cherry Shrimp without issue. If Cherry Shrimp feel threatened they will most likely retreat into hiding in the plants around them. In general, Cardinal Tetra will avoid Cherry Shrimp, but could potentially go after Cherry Shrimp fry as a meal.

Cardinal Tetra and Guppies

Cardinal Tetras and Guppies make for great tank mates, but they do enjoy slightly different water parameters. They get along fine, and will typically not bother one another. Make sure that your tank is well cycled before you add in your Cardinal Tetras.

Where Can I Find Cardinal Tetra For Sale?

If you are looking to purchase Cardinal Tetras for your home aquarium, you will easily be able to find them for sale in local pet stores and online. Make sure you are purchasing them from a reputable breeder to ensure that you are getting a quality fish that is also disease free. It is a good idea to quarantine new fish away from others for a few weeks to observe if they are healthy before adding them into your established aquarium.

Cardinal Tetra vs Neon Tetra

Whether Cardinal Tetras are better than Neon Tetras is up for debate. Both fish are hardy, and considered easy to care for with minimal requirements. Both species get along well with others, and both can be placed in a community aquarium with other species of peaceful fish with no issues. Which fish is better depends on what you want for your own personal aquarium. Neon Tetras are slightly cheaper than Cardinal Tetras, but Cardinal Tetras tend to grow just a little bit larger than Neon Tetras do. Either fish you choose, you will be able to enjoy both equally. More so if you pick for yourself. If you can not decide, why not pick both? These species can be seen schooling together in the right conditions. Cardinal Tetras are not easy to breed in captivity, but it has been done. Most of the Cardinal Tetras that you see for sale in pet stores are wild caught, whereas Neon Tetras are easy to breed in captivity.

Are Cardinal Tetra Hardier than Neon Tetras?

Cardinal Tetras and Neon Tetras are both considered hardy fish, and both are susceptible to the same ailments and disease. Due to their ease in spawning while captive, Neon Tetras have conditioned themselves to accept a much wider range of temperature than Cardinal Tetras. This means that they are more forgiving if something goes awry in your aquarium. It is much more important to closely monitor the water parameters for Cardinal Tetras than it is for Neon Tetras, but it is still a good idea to establish a routine in water maintenance and care.

Are Cardinal Tetra Easier to Keep than Neon Tetras?

Neon Tetras are typically considered easier to care for than Cardinal Tetras, and they also will spawn more readily in the home aquarium if you are looking to breed them. This is due to Neon Tetras being bred in captivity for a long time. They have been able to adapt to a wider range of water parameters.

Difference in Care Requirement Between Cardinal Tetra and Neon Tetra

Neon Tetras have been bred commercially for so long that their species has conditioned itself to accept a wider range of water parameters than the Cardinal Tetra. This means that they could potentially be hardier than the Cardinal Tetra if something goes wrong with their aquarium.

Can Cardinal Tetra and Neon Tetra Live Together?

Cardinal Tetras and Neon Tetras both enjoy the same water parameters, and diets. Not only can they live together peacefully, but they will even school together. The key to the happiness of both species is to make sure that they are being cared for properly, and all of their needs are being met.

Fish Laboratory

With decades of collective fishkeeping experience, we are happy to share the fish care tips that we've picked up along the way. Our goal at Fish Laboratory is to keep publishing accurate content to help fishkeepers keep their fish and aquarium healthy.

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