Can Cardinal Tetras Live With Guppies?| A Comprehensive Guide

Cardinal tetras are small fish that have been popular in the aquarium trade. You can find them for sale at any pet store and make excellent beginner fish because they are very hardy, peaceful, and colorful. Cardinal tetras generally live around four years if kept under good conditions. They are usually very good tankmates. But can Cardinal tetras live with guppies?

Yes, Cardinal tetras can live with guppies. Cardinal tetras and guppies are both small, active fish. They both are usually peaceful and can live together in the same tank. It would help if you kept Cardinal tetras and guppies in a community tank where the tank size is at least 20 gallons. Moreover, to keep them together, you only need to keep Cardinal tetras with small types of guppies such as neon, neons, and glitter.

If your aquarium has enough space for both fish, then there is no reason these fish cannot live together. But you should do some research before deciding if this is an appropriate option.

Can Cardinal Tetras Live With Guppies?

Owing to the non-aggressive attribute of Cardinal tetras, they can be tankmates of most of the fishes, including Guppies. However, Cardinal tetras are schooling fish that prefer to live in groups of at least six individuals. So it is advisable to keep them with other Cardinal Tetras or compatible species that will not bother them.

Guppy males tend to establish a pecking order within the school, but they rarely cause fatal injuries. Cardinal tetras can get along with guppies if there is a giant enough aquarium to have sufficient territory for each fish. Otherwise, it may be necessary to keep them in separate tanks.

While Cardinal Tetras are peaceful and compatible with most other species of community fishes, you should not keep them together with larger or aggressive tankmates. Such as Koi, Oscars, or Goldfish. Cardinal tetras are not very compatible with larger Tetra species such as Piranha and Neon Tetra because Cardinal tetras can prey on these more prominent species.

Are Cardinal Tetras Compatible With Guppies?

Cardinal tetras can live with guppies, but they will likely annoy the fish and sometimes even nip at their fins. They are peaceful fish that like to swim in schools of six or more, so keeping them together is not an option since Guppies only school up until there are four members. Cardinal tetras are good community fish and can live in smaller tanks.

Some of the problems that owners face when they keep Cardinal tetras with guppies are:

  • Cardinal tetras are nipping at the Guppy’s fins.
  • Guppies and Cardinal Tetra was fighting to defend their territories.
  • Cardinal Tetra’s too fast for the Guppy to catch and eat.
  • Cardinal tetras will sometimes eat the Guppy’s eggs.
  • Guppies are stealing Cardinal Tetra food when it falls in the tank from their owner, overfeeding them.

What Are The Similarities Between Cardinal Tetras And Guppies?

Although it sounds a little insane, Cardinal Tetras and Guppies have a lot in common. Cardinal tetras are members of the Characidae family, with Nannostomus eques as its most closely related species. At the same time, guppies are part of the Poeciliidae family.

However, some of the similarities between Cardinal tetras and guppies are:

Cardinal Tetras And Guppies Live In a Similar Environment

Cardinal tetras and guppies live in similar environments. However, they prefer a pH between six and seven while Guppies thrive at slightly higher temperatures around 27-30 degrees Celsius, which is just right for Cardinal tetras to feel comfortable.

Cardinal Tetras And Guppies Both Breed Easily

Although Cardinal tetras lay eggs and guppies are livebearers, they both are straightforward to breed. They breed similarly, with the female releasing her eggs into the water after she has mated.

Cardinal tetra fry will hatch about 24-36 hours before becoming free swimming three or four days later. Guppies breed similarly with the female releasing her eggs into the water and then fertilizing them externally.

Cardinal Tetras And Guppies Prefer The Same Food

Cardinal tetra and guppies both feed on live food. Usually, Cardinal Tetras are omnivores and can eat algae. Thus, they prefer to be in a well-planted tank that you maintain regularly, while Guppies are predatory by nature and need a diet rich in protein like bloodworms or brine shrimp.

Cardinal Tetras And Guppies Are Both Peaceful Fish

Cardinal tetras and guppies are both peaceful fish. However, the Cardinal Tetra, which grows up to four inches long, may not be a good idea for a small aquarium. They need at least thirty gallons of water while Guppies can fit in five-and-a-half gallon tanks.

Cardinal Tetras And Guppies Are Both Active Fish

Cardinal tetras and guppies are both active fish. Typically, Cardinal Tetras have a slender body shape while Guppies have a similar type of body with their oval-shaped, slightly down-turned mouth.

Cardinal Tetras will swim back and forth in the aquarium, looking for food. But Guppies dart from place to place searching for something interesting to eat.

What Are The Differences Between Cardinal Tetras And Guppies?

Cardinal tetras and Guppies are both freshwater fish. But they do have their personalities and care requirements. Some of the differences between these two types of fishes are:

Difference In Size

Cardinal tetras grow about a three-inch-long, while Guppies can become a foot in length. Usually, Cardinal tetras are much skinnier in comparison to the bulkier Guppies. In addition, Cardinal tetras tend to be more aggressive, while Guppies are not. They also have a long, pointed mouth that is good for eating in small spaces.

Difference In Water Temperature

Cardinal tetras do best in water temperatures around 77 degrees Fahrenheit (25 degrees Celsius). They will die if the temperature goes below 70 or above 82 degrees Fahrenheit (22 to 28 Celsius). Cardinal tetras are native to the Amazon River, which is in tropical South America. Guppies thrive when water temperatures are between 72 and 82 degrees Fahrenheit (21-28C), so they need more heat than Cardinal Tetras does.

Difference In Habitat

Cardinal tetra lives in rivers and lakes in the Amazon. Cardinal tetras live together, sometimes migrating as far as 100 miles (160 kilometers) upstream at spawning time. Guppies live in shallow streams and rivers of North America and Central America, though some species may be present in brackish water and occasionally even saltwater conditions.


Guppies have a bright-colored body, especially the males, while Cardinal Tetras are a duller brown or gray. In addition, Cardinal tetra has red patches on its fins and body that glow when light shines on them. Finally, guppies only have black dots at the base of their tails and some orange lines running from head to bottom.

Difference In Social Behaviors

Cardinal Tetras are more territorial than Guppies. These fish will fight with other not Cardinal Tetras or are of the same species, especially if food is scarce. You should keep them in schools of at least six fish to avoid this type of behavior.

Guppies can live together peacefully as long as they have enough space and hiding places like plants or rocks with holes between them where one Guppy can squeeze itself and stay hidden.

How To Keep Cardinal Tetras And Guppies Together?

Cardinal tetras and guppies can live together in an aquarium, but it is not a good idea to put them into a tank since they are predators. In addition, Cardinal tetra fish will eat small fish, which could be the poor Guppy.

However, some of the ways to ensure Cardinal tetras and guppies live happily together are:

Install A Filter

Cardinal tetras and guppies can live together if you install a filter that will make the water in your fish tank cleaner. However, Cardinal Tetra Fish cannot survive for more than three days without oxygen, so they must have access to clean water at all times.

Choose A Bigger Tank

Cardinal tetras are small fish, so they will only survive if Cardinal Tetra Fish Tank is big enough. So, installing a tank that can provide at least 20 gallons of water to each Cardinal tetras is the best option for your guppies.

Add More Plants To The Aquarium

Adding Cardinal Tetra Plant in the aquarium creates more hiding places for Cardinal Tetra Fish and Guppies, reducing competition. In addition, some of the plants can be live plants like java moss, Anubias, and ferns.

Improve Cardinal tetras Water Quality

It would be best if you cleaned the tank regularly with an aquarium vacuum. Cardinal Tetras do not like water quality issues such as ammonia, nitrites, and high levels of nitrates. All these chemicals can even kill them. So, it is best to use a high-quality filter for your Cardinal tetra.

Add Cardinal tetras to the tank after Guppies.

It is a good idea for you to add Cardinal Tetra fish only after the full growth of your Guppy. So they can swim freely in the tank with Cardinal tetra without worrying about predators.

Feed Cardinal Tetras Separately

Feeding Cardinal Tetra fish in a separate container with no Guppy can reduce competition among them. So, both of them will get all the nutrition they need for healthy and happy living.

Cardinal tetras will eat flake food, frozen bloodworms, tubifex worms, and live foods like brine shrimp and blackworms. Guppies can also eat these types of food, but it is better to feed them with commercially prepared aquarium fish flakes.

Some FAQs

Can I Breed Cardinal Tetras With Guppies?

Yes, Cardinal Tetras will breed with Guppies if they are in the same tank. However, you may want to separate them when the breeding time comes around. Cardinal Tetra fry is more likely to be prey of an adult Cardinal Tetras or other fish in your aquarium.

Are Cardinal Tetras And Guppies Competitors For Food?

They aren’t competitors for food, but they have different diets, so you need to feed them accordingly. For example, Cardinal tetras eat more live foods than guppies, but both require a diet that consists of live, frozen, and flake foods. They also enjoy munching on plants, whereas Guppies do not have this habit. 

What Is The Ideal Tank Mates For Cardinal Tetras?

Cardinal Tetras can live with Cardinal tetras, Glowlight Tetra, Congo Tetra, and most South American fish, including Danios. However, you cannot keep them in a tank with larger fish such as Cichlids or Goldfish. This is because Cardinal Tetras are schooling fish that need to live in groups of at least six Cardinal tetras.

Are Cardinal Tetras And Guppies Easily Distinguishable?

Cardinal tetra fish is straightforward to tell apart from Guppies because they have red markings near their tail and fins, whereas guppies do not. They also have a black marking on the caudal peduncle. Cardinal Tetras are part of the Characidae family, as well as tetras and barbs. They can grow around two inches long but usually only reach an inch or so when fully grown.


Summing up, Cardinal tetras are a very friendly fish that will become great tank mates for your guppy collection. In addition, Cardinal tetras and guppies have similar needs, making them perfect companions to one another in the same aquarium.

If you plan to keep Cardinal tetras and guppies together, you should be attentive to their behavior and watch for any aggression. Hopefully, this article has helped you understand Cardinal tetras and their compatibility with guppies.

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