Why Do Swordtail Fish Eat Their Fry? (All You Need to Know )

Lauren Kiekbusch
Why do Swordtail Fish Eat Their Fry

If you don’t properly care for your swordtail fry, their parents or other fish will eat them. Like all other livebearers, Swordtails lack maternal instincts and, as a result, will eat their young soon after birth. But why do swordtails consume their fries in the first place?

Swordtails are peaceful fish, but you’ll need to take numerous precautions to keep your newborn fish secure until they reach juvenile status or are large enough to escape their parents’ mouths.

Do you want to know why the swordfish eat their fry? Continue reading this article and gain more knowledge.

Also worth reading;

  1. Swordtail Fish Fry Care – How to Care for Baby Swordtails?
  2. How Long Are Swordtail Fish Pregnant For?
  3. Do Swordtail Fish Sleep?- You Might Be Interested To Know
  4. Why Do Swordtail Fish Eat Their Fry?( All You Need to Know )

Why Do Swordtail Fish Eat Their Fry?

There are different reasons why swordtail fish always eat their prey when they are raised together. The tiny fry’s movement imitates that of live food. Swordtails, like other fish, are genetically programmed to catch these little creatures. They have no idea that these little moving animals are their fry.

Hunger is another reason why mother swordtails consume their young. They may not touch the babies if you feed them the right food. Unfortunately, most low-cost brand foods lack the nourishment that your fish requires.

As a result, even if you provide your fish enough, they may be hungry. Fish, by the way, are constantly hungry.

I’ve highlighted some of the most common strategies for preventing swordtail fry from being eaten by their parents or other fish in the section below.

Ways To Save The Swordtail Fish Fry

Swordtails, as previously established, lack maternal instincts. As a result, you’ll need to keep the fry safe until they’re big enough to consume. Separating them from adults is one of the most successful strategies.

You may add more floating plants to the tank to disguise the young ones, but this strategy is less effective. To separate juvenile fish from the adults, some individuals choose to employ breeding traps. This may cause them to become more stressed, resulting in earlier births.

To avoid stressful situations in your aquarium, either remove the adult swordtails or the young ones and place them in a different one. If you don’t want to transfer the plants, remember to add more to the aquarium to camouflage.

Measures To Take To Ensure That The Swordtail Fries Are Safe

There are different ways that you can use to protect your swordtail fries which conclude the following.

1. By Use Of A Breeding Box

A breeding box is purchased at any pet store to protect your swordtail fry. The low-cost device comes in the form of a plastic container that can accommodate your pregnant swordtail.

However, it would be best if you did not put the fish in it until it is ready to give birth, as this may cause stress to the fish.

The breeding box is divided into two parts and floats in the tank. The pregnant fish will be housed in the top compartment, while the fry will fall to the bottom chamber through the slim case between the base and principal issues.

The mother will no longer be able to access the fry in the lower compartment after that. The baby fish may swim to the top chamber through the space between the bottom and full containers, though this is rare.

As a result, you’ll need to remove the swordtail from the top box and deposit it in the community tank when it gives birth. You’ll also need to remove the plastic piece that separates the bottom compartment from the top chamber in the breeding box so that the baby has enough room to swim.

Remember that the breeding box is not a good place to keep the fry for more than a few days because the water will likely stagnate. If you wish to keep the fry in the trap, you’ll need to replace the water with that from the community tank regularly.

Flies are tiny and should be raised in their aquarium to avoid swimming into the communal aquarium tank and being eaten by adult fish. Two pregnant females can be housed in a breeding box, which also serves as a haven for the fry after they are born.

2. By Use Of Living Plants

If you wish to maintain the fry in the communal aquarium tank, you’ll need to add extra floating plants to provide them somewhere to hide. Plants that are dense and bushy are ideal. Hornworts, guppy grass, java moss, and water lettuce roots are some of the plants that help infant swordtails survive. For around two weeks, the plants will provide appropriate cover, following which they will be robust and large enough to escape the adults.

3. Taking The Adult Swordtails Out Of The Tank

It can be challenging to catch the newborn fry at times. Remove all of the adult swordtails from the tank and leave the fry to grow to prevent inconvenience. You’ll have shielded kids from any hungry adult this way. Furthermore, this action will benefit the fry by reducing waste in the water. To remove mature fish from the community tank, use a mesh net.

If you maintain swordtails with other communal fish, you should remove them because they will hunt down the young fry.

When Can The Swordtail Fry Be Put Together With Their Parents?

You must first sew and separate the swordtails before introducing them to the community aquarium tank. Do so as soon as possible. Check the anal fins in males on their undersides to determine the sex.

Males have long, pointed anal fins, while females have rounded, fan-shaped fins. Separating males and females will make them more agitated, and they will battle for dominance as a result.

When a fry has reached six months, it is ready to breed and can be placed in the communal aquarium tank. Maintain a ratio of three females to one male.

Swordtails do not have a sex change. It will take longer for the baby swordtails to show their sex. They all appear to be females, but males do not grow the anal fins and long tails until later in life. There are two parts to this process.

When the fry is younger, they may exhibit masculine characteristics, but they will eventually have a petite, thin body shape compared to the other swordtails.

Many people mistake late-developing male swordtails for females, but this is not a good idea. They have heavier bodies than early male swordtails and mature into dominant males after gaining male characteristics.


Swordtails are great for a communal aquarium because of their calm nature. The first few months of the fry’s life will be crucial. Good water conditions and high-quality food will aid the development of healthier, more beautiful swordtails.

Breeding and breeding swordtails are enjoyable, but doing it for profit is a different matter. Keep the lights on for 12-16 hours per day for healthy growth.

It is not essential if the light is bright or strong, but it will aid in the prevention of spinal abnormalities. Fish also require rest, which necessitates turning off the light from time to time. Allow them to be in the dark for 6-8 hours.

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