Swordtail Fish Fry Care – How to Care for Baby Swordtails?


Swordtail Fish Fry Care – Wojciech J. Płuciennik (CC BY-SA 4.0)

If you do not have swordtail fish in your home, you might think that there is only a little to learn about them.

That is what one of my co-workers used to tell me. In addition to that, he told me that the world of swordtails is full of surprising events.

Apart from giving birth to around 80 babies at a time, a female can change into a male while still in the mid-life and they eat their babies.

ou might not believe the later, but a swordtail will deliver between 5 and 80 fry at a time. For all the fry to grow to full size, you will have to care for them properly and keep them safe from the adults.

How Swordtail Fry are Born?

Any swordtail that is 3 months old is ready to breed. Therefore, if you do not want them to produce more swordtails, you will have to separate the males and females because they will mate if you leave them together.

Identifying a female or male swordtail is not a hard task because the males have a sword-like anal fin, known as the Gonopodium, while the females feature a fan-shaped anal fin. For your swordtails to breed, you will not have to do anything else apart from putting the males and females in one tank.

After the breeding, the pregnancy will last for only 28 days. During pregnancy, a female will have a larger belly and will feature a gravid spot near its anal fin.

Pregnant swordtails do not exhibit mood swings but for good health, you will have to maintain good tank conditions. When the fish is ready to give birth, you will have to move it to a separate tank for it to deliver smoothly.

Your male swordtails are the biggest threat to your pregnant females because they can get aggressive towards them, which can lead to stress. Avoid keeping the swordtail in a breeding box because it does not provide enough space for swimming. It can also lead to early birth or even abortion.

Some aquarists, especially those in the beginner level, do not know how a pregnant swordtail looks like and it is, therefore, hard to remove it from the community tank in time. To transfer yours in time, you should know what to look for.

If your fish stops eating, stops swimming or slows downs, it is time to transfer it to another tank. The fish might also sink to the bottom or remain in one spot for a very long time if it is pregnant. After it pops the fry, you can move it to the community aquarium tank to keep the swordtail fry safe.

Saving the Swordtail Fry

Mostly, swordtails and other livebearers eat their babies. Therefore, if you already have a separate aquarium tank in your home, you can transfer the pregnant swordtail there. If you do not have one, you can still save your fry. Here are the steps to take:

  1. If you do not own a breeding aquarium tank for your pregnant swordtails, or somewhere to place the pregnant swordtail to drop the fry, use a big plastic container or glass jar to separate your pregnant fish from the others. Extract the female from the community tank when she is ready to give birth and return immediately she pops the fry.
  2. To keep the female separated from the fry after delivery, you will have to buy a breeding box. The box is a plastic container or small mesh that will float in your main aquarium tank. One great thing about the breeding box is that it will eliminate any worries about the aquarium water conditions. Water will flow freely through the breeding box and the fry will remain trapped inside the box for their safety. Extract the female from the breeding box immediately she gives birth to provide her with adequate swimming space.
  3. Add plants to the aquarium tank to provide the fry with more hiding places. Live plants like hornworts, guppy grass, java moss and water lettuce roots will increase the survival rate of your swordtail fry. The plants will cover them for several weeks until they are large enough to start escaping from the adults. Aquarium accessories will also work.

The fry will become a juvenile in four weeks. The period highly varies from one fry to the other, but if the condition of water in your aquarium tank is good, you should expect all of them to turn into juveniles within six weeks.

Juveniles are usually large enough to survive in the community tank, but the adult swordtails might be aggressive towards them. To keep them safe, you will have to plant more heavy greens. That will provide them with the hiding spaces they require to avoid harassment. When kept away from the predators, the survival rate of swordtail fry is usually high.

Feeding Swordtail fry

Swordtails are omnivores when in the natural environment. They feed on insects, plants, invertebrates and algae. You will have to provide them with a balanced diet, which can mimic what they eat in the wild for them to remain healthy and grow fast.

Avoid the low-quality feed because they can even cause diseases. Swordtail fry like liquid fry and newly hatched brine shrimp. Provide them with as much live meat and protein as possible. Some other live foods include daphnia, mosquito larvae and bloodworms. You should be careful when choosing the live feed because they can transfer diseases to your swordtails.

Moreover, you can feed them with very tiny yolk pieces from the boiled eggs. Start by crushing the yolk and drop the small pieces in your aquarium tank. Add more live plants to provide enough vegetation for the babies.

Feed them with vegetable supplements and crushed fish flakes and spirulina for diversity of diet. Swordtail fry eat in smaller proportions and they will feed more often. Therefore, drop food in small proportions several times in a day. Do not overfeed them – provide them with the food they can consume within 3-5 minutes.

Swordtail Fry Tank Maintenance

I have heard most people claim that swordtails are the best community tank species they know of. In their natural habitats, swordtails can grow to around 6 inches because they get enough room to grow to that size. Although the swordtails we get from the stores mostly grow to around 2.5 to 3inches, the size of your tank and the water condition will highly determine their size.

Most of the aquarists I have talked to told me that their swordtails grow slowly when they are in a breeding trap or a small aquarium-breeding tank. To ensure fast and proper growth, you will need a separate large tank for the swordtail fry.

The tank should not be as big as the community aquarium tank, but it should be bigger than your breeding trap. If your community aquarium tank is around 20 gallon, you will need a 10 gallon for the baby swordtails.

Experts claim that swordtails are resilient fish species. The sword is not functional, but the rate of survival of swordtails is better than that of any other livebearer. They can survive in not-so-good water conditions.

That should not mean that the bad water conditions would not affect their growth. Maintaining water conditions that are different from what experts recommend will lead to slower growth of the swordtail fry. Maintain a temperature between 64 and 83 degrees F and a PH between 7.0 and 8.3. The water hardness level should be between 12-30 KH.

If the conditions are different from that, the swordtail fry will take over six months to achieve the full size – 1.5 inches for the females and 2 inches for the males. Moreover, with bad water conditions, the swordtails might not attain the full size. So, for them to grow faster, maintain good water conditions.

Related Questions

How many can a female swordtail deliver at a time?

Swordtails can give birth to around 10-100 fry at once. After that, they will leave the work of caring for the young ones to the owner because the mother fish do not have maternal instincts for their young ones.

To care for the fry, you will require a separate aquarium tank to isolate them. Place more live plants in the aquarium tank or accessories to provide them with hiding places. The swordtail fry requires similar water conditions to those of the adult swordtails. Feed them properly so that they can grow faster.

What is the size of a newborn swordtail fish?

The average size of a swordtail fry will be below a ¼ inch (5-7mm). The size is very close to that of guppy fish fry. However, they will grow to around 1.5 inches or 38 mm within three months. By that time, they will be mature enough for breeding.

The swordtail fry are tiny but you will easily spot them in water after they are born. If you do not see them, then expect some issues in your aquarium tank. You can use a magnifying glass to find them. If you do not see any of them, the mother might have eaten them. They might also be hiding in the plants.

When do swordtail fry start eating?

Swordtail fry starts searching for food immediately after they are born. You can feed then finely crumbled flakes and newly hatched brine shrimps.

If you want to speed up swordtail fish growth rate feed them food that is high in proteins and fat. Swordtails will eat vegetables, live or frozen food as well any commercial flakes or pellets.

Feed them regularly and do frequent water changes in order to raise healthy and beautiful fish.

Questions and Answers

Cristina cearmel t Uayan January 29, 2020 Reply

my swordtail born babies today. what should i do to make sire that all the fry will survive?

    You should separate the fry in a new tank and make sure that water parameters are good all the time.

Tom Capolino February 9, 2020 Reply

Hello Fabian, Are partial water changes necessary in my 10 gallon swordtail fry tank? If so how much and often do you recommend?
Appreciate you dedication to the hobby.

    It really depends on the tank setup. If you have good filtration, lots of plants, you might get along with no water change. However, if you want to grow your fry faster, you need to do partial water changes.
    Some bigger fry release hormones, that will slow down the growth of smaller fry even more. So with partial water changes you can eliminate some of the hormones in the water and help smaller fry catch up in growth.

Hello, my swordtail recently gave birth and I am curious about how long it will take for me to be able to determine the fry’s gender.

    It takes about 4-6 weeks until you can determine the fry’s gender. In smaller aquariums, it might take even longer, because the fish won’t grow as fast as they do in bigger tanks.

Leave a Comment

Your email address will not be published. Required fields are marked *