Do Cardinal Tetras Eat Their Babies?: Misconceptions And Truth

Cardinal Tetras are one of the most popular tropical fish. They come in various colors, but they all have very similar needs and requirements for their care. Cardinal tetra fish are freshwater aquarium fish that look spectacular when added to an office or home tank with other species. But some owners complain that Cardinal tetras tend to eat their babies.

Do Cardinal tetras eat their babies? The answer is not a simple yes or no. Cardinal Tetras are generally very peaceful and can live with many other species of fish. But they may eat their offspring if the tank is too small to support them all at once.

This article will explore more about Cardinal tetras and what you need to know about Cardinal Tetras and their life cycle. So, read on.

How Do Cardinal Tetras Produce Babies?

After reaching sexual maturity, Cardinal Tetras will usually produce babies every month year-round. These fish have babies by laying eggs.

Cardinal Tetras will lay their eggs in bunches that often contain 300-400 eggs. Their eggs are tiny, measuring only about 0.12 millimeters in diameter. After laying eggs, Cardinal Tetra babies hatch from these eggs within 48-72 hours, depending on the temperature of the water.

The male Cardinal Tetra will protect its fry until they are ready to survive on their own, about three weeks long.

How Long Do Cardinal Tetras Keep Babies?

Cardinal tetra parents will protect their eggs for 24 to 48 hours after they lay the eggs. The period between when the mother lays her eggs and then removes them from her body with a particular organ called an ovipositor. Cardinal tetra eggs will hatch within four to six days after laying and fertilizing the eggs by male cardinal tetras.

If you have an unknown plant in your aquarium, then remove it before Cardinal Tetras lays their eggs on them. It is because some plants can be dangerous for both of these life forms. So, it is better to eliminate it than take the risk.

Do Cardinal Tetras Eat Their Babies?

Cardinal tetras are not cannibals. They do not feed off their young. Cardinal tetras are schooling fish, so they do not need to eat their babies for themselves or the group of Cardinal Tetras to survive.

But some species of Cardinal Tetras may eat their babies if they feel stressed out. Cardinal tetras new to an aquarium will often nip at the fins of other Cardinal Tetras for them to establish territory. They can also attack and kill each other during territorial disputes or when tankmates pick on one Cardinal Teta because it is sick. They may also eat their young if they fail to adapt well to the aquarium environment.

Why Do Cardinal Tetras Eat Their Babies?

Not all, but few species of Cardinal tetras might also eat their babies. There are a few reasons why Cardinal Tetras will eat their babies or eggs. They are:

When They Are Unhappy With Tank Condition

Cardinal tetras might also eat their babies when they are unhappy with the tank condition. When Cardinal Tetras feel there is a threat to them somehow, this will trigger Cardinal Tetra’s behavior of eating its babies. For example, when the tank is dirty and lacks suitable hiding spots for Cardinal Tetras, they feel unsafe, and they might eat their babies. It is a Cardinal tetra’s way of trying to save its own life by protecting itself from the danger it feels in an environment that doesn’t support Cardinal fish well enough.

When They Are Too Young

Cardinal Tetras are predators when they are too young. In addition, Cardinal tetras might eat their babies if they are tiny, and the babies resemble prey to Cardinal Tetra’s eyes. Thus, it would help if you waited until Cardinal Tetra becomes bigger before introducing more Cardinal fish into your tank so that it will not mistake its baby Cardinal Tetras as food but instead recognize them as family members.

In New Environment

Cardinal Tetras might eat their babies if they are in a new environment. It is because Cardinal tetras are very sensitive to changes.

If the difference is big enough, Cardinal tetras will not adjust themselves well with it. It could cause Cardinal Tetra’s parents to think that there’s something wrong or different about their eggs/babies because of the new environment. Cardinal Tetras might eat their babies as a result of this wrong-perception thinking.

Lack Of Enough Space

Cardinal Tetras are one of the most famous shooling species. Cardinal tetras like to swim together in groups. If insufficient space is available, Cardinal Tetra pairs might not have enough room for each other. Moreover, their babies, once they hatch or spawn, egglaying will increase competition between Cardinal Tetra couples leading them to eat any baby fish.

Prey-Predator Relationship

Larger species of fish like Piranha, Pike Cichlid, and other predatory species of freshwater aquarium fishes can pose a risk to Mollies and their babies as well. Cardinal tetra couples that eat any baby or eggs do so because they think it will help protect the babies from predators.

Supply Of Food

Cardinal Tetras eat live foods such as brine shrimps and worms in aquariums. If your Cardinal tetra parents cannot find enough food for their baby, Cardinal Tetra male-female pair might resort to eating their babies to survive. Cardinal Tetra breeders also have the same problem in finding enough food for their Cardinal tetras during breeding.

When Cardinal Tetras Are Sick

Cardinal Tetras are prone to many diseases and health issues. Therefore, Cardinal Tetra parents under stress might eat their babies, eggs, or fry as a means of protecting themselves from possible conditions that can affect them and the baby fish they have produced.

How To Stop Cardinal Tetras From Eating Babies?

Cardinal tetras are a peaceful fish species, but Cardinal Tetra Fish will eat their babies. They are small and easily swallow baby fish that are not strong enough to swim with them at the surface of your aquarium.

Here is a guide to stop Cardinal tetras from eating their baby Cardinal Tetra Fish:

  • Keep your aquarium in low light conditions because they do not like bright lights, so they will swim away when too much light comes into your Cardinal Tetra Fishtank. Cardinal Tetra fish prefer to swim in the middle of your aquarium because it is where they feel safe and secure from predators lurking at either side of Cardinal Tetras’ habitat.
  • Reduce the number of Cardinal tetras you have so that there is no more than one male Cardinal tetra for every ten females. Cardinal Tetras are peaceful fish. But they do not prefer colossal schooling. So, keep only a few Cardinal Tetras in your aquarium tank if you want to prevent them from eating their babies.
  • Keep many places for Cardinal Tetra hiding spots where the baby fishes can hide when adults eat small Cardinal Tetra Baby Cardinal Tetras. 
  • Set up plants in your aquarium tank because Cardinal tetras love swimming around plants where their babies can hide.

Some FAQs

What Do Babies Of Cardinal Tetras Eat?

Cardinal Tetras, as babies, will eat the same things Cardinal tetra adults do. So, for example, you can feed them baby brine shrimp, infusoria, and crushed flake foods.

Do Cardinal Tetras Eat Babies Of Other Fish?

No, Cardinal Tetras do not eat the babies of other fish in their tank. However, this is an untrue myth about Cardinal tetra’s behavior and needs some correction.

Cardinal tetras live peacefully with most fish species until they feel safe and get space to move with optimum water conditions. These fish only attach or eat other species when they feel threatened or stressed out.

Do Cardinal Tetras Eat The Fish They Live With In-Tank?

Cardinal Tetras are very peaceful, but they can attack larger predatory fish entering their territory or threatening them. Cardinal Tetras will not eat their fish tank mates.

However, if they feel threatened, they may defend themselves by attacking the other Cardinal tetras. Or prey on small feeders that you have temporarily introduced into their territory.

Are Cardinal Tetras Aggressive?

No, Cardinal tetras are not naturally aggressive. They will live well with other Cardinal Tetras, Danios, Gouramis, Bala sharks, Hatchetfish, and most community fish. But sometimes, Cardinal Tetra may be aggressive towards other Cardinal tetras, usually due to overcrowding.


Summing up, Cardinal tetras are colorful fish that enhances the beauty of your aquarium. These fish eat insects, plants, and small invertebrates such as baby shrimp or daphnia. They will also eat their own young if they don’t have enough food to go around.

Cardinal tetras are peaceful fish that can get along with most fish species. So, it would be best if you kept them in schools of at least five. However, they can also live up to ten years to be a long-term commitment for the aquarium owner.

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Remember to check out our Cardinal tetra care guide if you want to learn more about these exciting fish!

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