What Do Cardinal Tetras Eat In The Wild?

Ever since the popularity of Cardinal tetras increased, there have been a lot of assumptions about them. But with those assumptions come some interesting questions about the natural habitat of Cardinal tetras or what they eat in the wild.

Cardinal tetras get a lot of their food from the plants and algae in their wild habitat. However, they also eat small insects, insect larvae, zooplankton – tiny organisms that live in water or phytoplankton, microscopic plants present in aquatic habitats. Besides this, some of the wild’s undeniable food for Cardinal tetras are worms and small crustaceans such as copepods, amphipods, and cladoceran.

Today, we will be exploring more about the habitat and the eating habit of these fish in the wild. I hope you find this post informative.

What Is The Natural Habitat For Cardinal Tetras?

Cardinal tetras are native to South America and live in the Amazon River basin. They prefer slow-moving water with proper oxygen but not too much flow. They live in densely shaded, heavily vegetated areas of the river.

Cardinal tetras are omnivores that eat both plants and animals. In their natural habitat of South America, they feed on invertebrates such as insect larvae, worms, and small crustaceans. However, they also serve a crucial role in the ecosystem by providing food for larger fish, birds, and other predators.

Usually, these fish can adapt to different water conditions, but they prefer warm water with a neutral pH between 70 and 75 degrees Fahrenheit.

What Do Cardinal Tetras Eat In The Wild?

Being omnivores in nature, Cardinal tetras had a lot of food choices in the wild. In general, they feed on various insects and invertebrates living in water, such as worms, larvae, copepods, and other tiny crustaceans found along rivers or lakes. The adult Cardinal tetras also feed on zooplankton that drifts near the surface of the water.

In addition to the usual diet of insects and invertebrates, river shrimp (Macrobrachium spp.) also form part of their natural food source. River shrimp is a significant component in Cardinal tetra’s diet since they can grow to almost six inches long – big enough for juveniles and adults to feed on them.

Moreover, even though they live in the wild, Cardinal tetras also feed on vegetation. Cardinal tetras also eat algae and other plant materials whenever available.

What Is The Best Diet For Cardinal Tetras?

Cardinal tetras need both plant and animal material in their diet. They typically eat fallen fruit and soft vegetation from the wild but feed on small insects like worms and snails. Thus, it is best to provide them with a combination of fruits, vegetables, and protein. In the wild, cardinal tetras eat various foods in different seasons to make up their diet.

To give them a varied diet for aquarium care:

Frozen Bloodworms

Cardinal tetras enjoy eating bloodworms. Frozen bloodworms are high in protein and promote good coloration. Other suitable options include brine shrimp or daphnia (for smaller fish). If you can’t find these, then try freeze-dried bloodworms or tubifex.


Daphnia is live crustaceans that also promote good coloration and help to prevent disease in the fish’s digestive system. However, it would be best to feed them sparingly as they contain a lot of chitin (a fiber), making them difficult to digest and can cause constipation.


Peas enhance the coloration of cardinal tetras and keep their digestive system healthy. In addition, they contain high levels of vitamin C, which helps to boost immunity in fish. Frozen peas are a good option for aquarium care because they do not go bad quickly like fresh ones when left out at room temperature (due to the high water content).


Spinach and other leafy green vegetables enhance coloration, reduce stress in fish (from low-nutrient foods), and provide vitamin C. They also help to keep the fish’s digestive system healthy.

Cooked Oatmeal

Cooked oatmeal or rice can be a substitute for peas and other vegetables in aquarium care. Usually, they contain high amounts of vitamin B (niacin), which helps reduce stress, build immunity, and prevent diseases in cardinal tetras. At the same time, they digest their food because it is easier to digest than chitin.

Cooked Potato

Cooked potato can substitute oatmeal or rice in aquarium care, but it does not contain vitamin B (niacin). It is high in starch and sugars that cardinal tetras cannot metabolize quickly because their digestive system is different than humans.

Cardinal tetras cannot handle large amounts of carbohydrates and starch. As a result, this can cause bloating, constipation, and swim bladder problems.


Fruits are high in vitamin C and also make cardinal tetras more colorful. They work well as a treat to feed your fish every once in a while because they contain lots of sugars that are not good for their digestive system if provided too often. It would be best if yIn addition, you tried feeding them papaya (high in papain), which helps reduce stress and increase immunity.


Supplementing nutrients can help to keep cardinal tetras healthy too. You should try TetraMin Tropical Medley Color Enhancing Food for this purpose, as they contain high amounts of vitamin C that boosts their immune system while keeping them colorful at the same time.

Will It Be Good To Use Wild Foods In The Diet Of Cardinal Tetras In Captivity?

I believe that it is crucial to try and replicate the diet of cardinal tetras in the wild as much as possible. It will mean using many different foods from their natural habitat to get a varied, healthy diet.

However, some of these foods may not be suitable for the captive environment. So, you must be careful when you introduce new items to your fish. Some of the things that you need to consider when you give your fish the wild foods are:

What Are The Risk To Your Cardinal Tetra? Will The Risk Be High Or Low?

The first thing you need to consider when introducing new foods into your cardinal tetras’ diet is how risky they are. Some plants and insects may contain parasites, toxins, and chemicals that can cause illness in humans and animals. These include ciguatera fish poisoning, botulism, and cholera.

What Are The Benefits Of Wild Foods In Cardinal Tetras’ Diet?

You need to weigh whether there are any benefits for you or your cardinal tetras if you choose certain food items over others. It may seem strange that some things might be better for your fish, even though they are ‘wild’ foods. However, it would be best to consider whether your cardinal tetras readily accepts the food items you feed them.

Wild foods are far less likely to contain any toxins or harmful parasites. Besides this, these foods are more familiar to your fish. So, your Cardinal tetra will enjoy them without being picky.

How Much Of Food Can I Give My Cardinal Tetra?

It would be best to consider how much of the food you should give your cardinal tetra. If they do not eat all you give them, they will ensure that they do not waste anything.

You should remove the uneaten food. Otherwise, this food will go back into the environment and contaminate other animals or plants living there. Leaving this food also increases the chances of illness and disease in Cardinal tetras,

Some FAQs

What Are Some Natural Foods They Might Prefer?

There are several different food sources that cardinal tetras might eat in their natural habitat. These include seeds from grasses/plants, invertebrates such as insects, small crustaceans, worms; algae; other plant materials.

What Would Be A Good Habitat To Use In Captivity?

In captivity, a cardinals’ tank should be at least 20 gallons in size with dense vegetation to give them enough hiding spaces from predators. The water temperature must also remain between 20-26 degrees Celsius at all times.

What Are Some Of The Foods That I Can Give My Fish Regularly?

Cardinal tetras are omnivorous fish, so they eat both plant and animal material in the wild. Therefore, they will need a mixed diet in captivity, which consists of food that is high in plant and animal content. Some appropriate foods include bloodworms; brine shrimp, daphnia (live or frozen); tubifex worms; mosquito larvae/pupae; artemia, plankton powder mix.

What Are The Foods That You Should Avoid In Cardinal Tetras Diet?

There are several different types of food that you should not feed to cardinal tetras. These include meat; fish, and fatty foods such as cheese, chocolate, and avocado skin/pips (avocado flesh is delicate); dairy products; high-fat or sugary fruits; popcorn kernels; large seeds which could become a choking hazard.


Hopefully, this blog has enlightened you on the diet of cardinal tetras. The next time you are in your local fish store, stop and look at this beautiful freshwater tropical community fish before purchasing it.

However, you must be careful that all fish have unique preferences. So, there is no definite way to claim that your fish might enjoy the food your choose. It all depends on trial and testing.

I wish you the best of luck in choosing the best for your Cardinal tetras!

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