Can Swordtails Be Kept Alone?

So you’re thinking about getting a swordtail but are wondering, “Can Swordtails be kept alone?” 

Swordtails shouldn’t be kept alone. Those fish are highly sociable and they need to be in groups of four or more in order to enjoy a healthy, happy life. 

You can try to keep a single Swordtail and keep it stimulated, but it’s not recommended. It’s not just the social nature of Swordtails, as these fish exhibit negative reactions if they live alone for a long time. Read on to learn more.

Can Swordtails Be Kept Alone?

You can keep swordtails on their own, but both their mental and physical health will be affected.

Swordtails, like most live-bearer fish, have a fast reproduction rate. That could quickly overpopulate the tank faster than you can handle.

This is why some pet owners try to keep a single Swordtail. Doing that is possible, but it will require a lot of stimulating effort from your side.

That’s because Swordtails are highly sociable fish. They need constant stimulation in their environment to remain healthy.

You could help your lone Swordtail by placing its tank in a room full of visual and audible stimulations. The living room, for example, is a good place to keep your Swordtail occupied with distractions.

You should also have a spacious aquarium for it to explore. A 15-gallon tank should be enough. Additionally, fill their home with aquarium toys to give more stimulation to your lone Swordtail.

These suggestions will compensate for the loneliness of your Swordtail. However, it’s still best to give your Swordtail some companions to ensure that it lives a long and happy life.

Red Wagtail Swordtail

What Happens If You Keep a Lone Swordtail?

Whether you do your best to keep your Swordtail occupied or ignore it entirely, there are some issues that it could face when it’s kept alone.


When a Swordtail is left alone for prolonged periods, its movement will significantly be reduced. The fish will become inactive, lazy, and bored.

Swordtails are active fish that not only enjoy constant stimulation; they need it!

This stimulation could come from various sources. Tank companions are the main source of such stimulation.

Lights, sounds, and toys are other methods you can use to keep your Swordtail occupied. Yet, the fact remains that Swordtails need tank companions to live happier and longer.


All the body organs need to be fulfilling their functions in the required manner to remain healthy.

Let’s talk about humans, for example. When we overwork our muscles; we might tear them by accident.

On the other hand, if we completely stop using muscles, muscle atrophy occurs. It’s a condition where muscles get smaller.

The same scenario happens with Swordtails. When they get bored and lazy, they move a lot less than they usually do. That slows down most of their body functions.

Once their movement is reduced, their health starts to gradually deteriorate.

When a Swordtail is left alone for long periods, it starts to show a manifestation called sickness response. It’s a mental condition that makes the body more susceptible to diseases and infections.

You can keep your swordtail occupied with many stimulations. However, nothing tops a tank companion.


The lack of movement and the increased susceptibility to diseases apply constant pressure on your lone Swordtail. The fish feels that something is wrong. This builds up anxiety and stress over time.

A stressed fish may eat less, move less, and responds less to stimuli as well. In extreme cases, Your anxious Swordtail might jump out of the tank entirely if there’s no cover on it.


This isn’t something you’d notice from Swordtail when it’s alone. It’s something that happens after you introduce new mates to the tank.

Living alone for a long time, mixed with all the built-up stresses is a good recipe for aggressiveness. That could even happen towards new tank mates of the same species.

Luckily, solving this issue isn’t hard. If you decide to introduce new tank mates to your Swordtail, don’t do it directly.

By that, we mean that you should place your new mates in a separate tank. However, this tank should be right next to the old one so that your lonely Swordtail can see the new mates.

After one week, try to put all the fish in the same tank and observe. Some bullying might happen on day one, but that’s considered normal.

If the bullying persists, take out your original Swordtail and place it in the new tank. The smell of the other fish in that tank will help it to mark the new mates as “safe.”

After that, it’s just a matter of rinse and repeat till the fighting stops.

Final Words

Can Swordtails be kept alone? No, they won’t live long and the poor fish will be stressed out most of the time.

If you don’t want to deal with the fast reproduction but want the best for your Swordtail, get it tankmates of different species.

Peaceful fish species are your optimum choice. Cory Catfish (Coryodas) and plecostomus are good tankmates for Swordtails.

Keep in mind that loneliness is a process that builds up over time. Your pet Swordtail won’t instantly go into depression the day you keep it alone.

If you need to temporarily isolate your Swordtail, that’s fine. However, in the long term, having a tank mate of the same or different species is essential for your Swordtail to have a good life.