Do Cardinal Tetras Eat Their Fry: A Look At Their Feeding Preference

Cardinal Tetras are a popular fish in the aquarium hobby, but they only grow to about two inches. They live in very fast-moving waters and eat smaller fish, making it challenging to keep them with other types of larger community fish. However, most owners also believe that Cardinal tetras also eat their fry.

There is no definite answer as to whether or not Cardinal tetras eat their fry, but there have been some interesting observations on this topic made by breeders. Cardinal tetra fry has a large yolk sack that they rely on to survive for up to three weeks after birth until developing a fully functional digestive system.

Some people have noted Cardinal Tetras are eating Cardinal tetra fry from birth, but other breeders insist this does not happen at all in an aquarium setting.

In this blog post, we will be looking at Cardinal Tetra feeding preference and whether they eat fry or not.

Do Cardinal Tetras Eat Their Fry?

Yes and no. It is a controversial question to answer that has no correct answer. Cardinal tetras are predatory fish that eat small insects, crustaceans, and other zooplankton in their natural habitat in South America. However, in captivity, Cardinal Tetras usually do not try to eat fry (baby Cardinal Tetras). Therefore, if you have a group of these fish, it is scarce for them to eat Cardinal Tetras fry.

Most Cardinal tetra parents will protect their young from the other Cardinal tetras in a tank. However, if you have one or two Cardinal Tetras that are not with a group of adults, then it is possible to eat all your baby fish because they prefer live food over anything else.

Why Do Cardinal Tetras Eat Their Fry?

Cardinal tetras are usually peaceful fish species. But sometimes, they end up eating their fries. There are a lot of reasons behind it. Such as:

Cardinal Tetras Eat Fry Due To Water Conditions

Cardinal tetras are tropical fish that can adapt themselves to different water conditions. But, they can only survive in those conditions if the water is clean and clear. Instead, they eat fry due to poor water quality, which results from a dirty tank or insufficient filtration system.

Cardinal Tetras Eat Due To Lack Of Space

Cardinal tetras are very active fish that need a lot of space to swim. If there is not enough room for them, they will eat their fries to have more energy to explore the tank. These fish eat fry when they feel there is not enough space to swim freely in the tank.

Cardinal Tetras Eat Fry Due To Competition

Cardinal tetras are very social fish. They like to swim in groups all the time. Cardinal tetra eats their fry when they feel threatened by other cardinal tetras that may want to take over their territory or just because of competition for food.

If you have a community tank, you should always watch out for the cardinal tetra that eats its fry. These fish will eat fry when they feel threatened by other fish in a community tank or cannot find enough food to survive.

Cardinal Tetras Eat Fry When They Feel Stressed

Cardinal tetras are usually very sensitive to water parameters. So, if you find Cardinal Tetra Fry, it is likely that they were born in poor conditions. One of the reasons why Cardinal tetras eat their fry might be because the parents feel stressed out while giving birth to them.

Cardinal Tetras Eat Their Fry When They Are Hungry

Cardinal tetras are usually born in large numbers. They tend to eat their fries because they are already hungry and there is no other food source available at the time. For example, Cardinal Tetra Fry might be able to sense when it’s about feeding time based on smell or sound. When Cardinal Tetra fry cannot find any natural predators around them, they grow faster, and sometimes, Cardinal Tetras eat their fry because they are hungry.

Cardinal Tetras Eat Their Fry Because They Are Incompatible With Other Fish Species

Cardinal tetra fish eat fry to survive, but sometimes they eat their fries because of compatibility issues with other fish species in the aquarium. In addition, they usually prefer a smaller tank size and less vegetation. So it’s best to keep Cardinal tetra fry in a tank to grow into an adult fully.

How To Prevent Cardinal Tetras From Eating Fry?

A Cardinal Tetra may eat its fry for several reasons. The most common causes are lack of space, not enough hiding places in the tank, and feeling threatened by their young ones.

Once you have identified why Cardinal tetra eats its fry, it will be easier to prevent this from happening again in your aquarium or fish tank.

Some of the ways to prevent Cardinal tetras from eating their fry are:

Provide Enough Space

Cardinal tetras do not like to live in a crowded environment. Providing enough space for Cardinal Tetra and its fry will prevent the Cardinal from eating its fry. Cardinal Tetras need at least 30 gallons of tank space for a school of five fish and an additional 15 to 20 gallon per each extra Cardinal tetra in the aquarium or fish tank.

Keep The Tank Decorations To A Minimum

Cardinals like open spaces, so it is best not to overcrowd their living area with too many decorations. Unfortunately, Cardinal Tetras are also very territorial. They will not tolerate their kind or any other fish that resembles them.

Create Hiding Places

Cardinal tetras like to hide in caves and crevices during the daytime. So make sure you provide hiding places for Cardinal Tetras. You can either create them yourself using aquarium-safe rocks or driftwood or by getting artificial caves and crevices.  You can attach the artificial ones to the walls of the aquarium or fish tank.

Feed Cardinal Tetra With The Right Food

Cardinal tetras are omnivores, so it is best to feed them live foods such as brine shrimp, bloodworms, daphnia, tubifex worms because they are a great source of protein for Cardinal Tetra. They also enjoy eating flakes and plant matter. You need to feed them twice a day, once in the morning and again at night if you want to make sure that Cardinal Tetra does not eat its young ones.

Maintainance Of Water Condition

Cardinal tetra is like well-maintained water, so it is important to clean the tank’s water. Change 20 to 30 percent of tank or aquarium water at least once a week, vacuum the gravel before you change the water to remove any uneaten food.

Also, make sure the water has a temperature of 70 to 78 degrees, a pH of between six and seven, and has a water hardness level lower than 12. Cardinal Tetras can survive at higher temperatures but prefer it around 70 degrees.

Some FAQs

What Do Cardinal Tetras Eat?

Cardinal tetras are omnivores, which means that they eat both plants and animals. Cardinal Tetras will eat flake food once they become adults, but you can feed them smaller fish like guppies when they are still young to keep the Cardinal tetra fry healthy until it becomes an adult itself.

What Do Cardinal Tetra Fry Eat?

Cardinal tetra fry eats algae and small insects. They will also eat uneaten food from adult Cardinal tetras in the tank. Thus, this makes it easier for you to feed them since they can pick up leftovers when Cardinal tetra adults are not looking.

How Can I Feed Cardinal Tetra Fry?

Feed Cardinal tetras fry with a small net or by using the tip of your finger. Cardinal tetra fry will eat pretty much anything. They don’t even need daily feeding as long as there are food leftovers in the tank from adult Cardinal Tetras.


In conclusion, Cardinal tetras eat their fry, even when they are mature enough and grows to full length. This fish is a widespread species of tropical freshwater fish, and most people want to know if it eats its baby fish. 

Cardinal Tetras are a great fish to have in your tropical freshwater tank, and they make for excellent pets. If you want to gain more information about Cardinal Tetra, click on our website for details.

Thank you for reading.

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