How Many Swordtails in a 29 Gallon Tank?

Eight swordtails are the ideal number for a 29-gallon tank. Ideally, the ratio between males and females in a 29-gallon tank should be one to three, respectively. 

Whether you’ve been collecting fish for a while or are new to it, you’ve most likely come across swordtails. Swordtails are always recommended because they’re not a demanding fish species.

Not to mention the variety of colors you can choose from. If you’re going for a subtle look, orange or black swordtails will do the trick. Striped and red ones are there for a more exotic feel.

This brings us to the question of how many swordtails in a 29-gallon tank. Keep reading to find out!

How Many Swordtails in a 29 Gallon Tank?

A 29-gallon tank should house four swordtails More than four would be overkill since swordtails are an active and playful species that need to have their own space.

A male swordtail can reach 5.5 inches in height, while a female can reach 6 inches. Female swordtails are about 1 inch larger than males, although they lack the signature elongated tail.

The elongated tail is only found in male swordtails and is the easiest way to distinguish them from females. Aside from the swordlike tail, both genders appear identical.

Following the general measuring rule of “1 inch per gallon,” you’ll find that four swordtails are just the perfect number for a 29-gallon tank. Each swordtail requires approximately 6 gallons of water to lead a healthy life.

Orange and Yellow Swordtail

How Many Male Swordtails Can You Keep in a 29 Gallon Tank?

It’s never a good idea to keep two male swordtails in the same tank, especially for new fish owners. With that said, you should maintain the gender ratio of one male and three female swordtails in a 29-gallon tank.

You might be puzzled right now because swordtails are known for being peaceful and friendly. While this is correct, it doesn’t apply to male swordtails living together.

Having two males in the same tank can lead to food, mating, and territorial aggression. As a result, there’ll be a constant feud between male swordtails, which will often result in:

Injury and Death

Since male swordtails want to assert their dominance, they’ll show that in the form of bullying.

They harass each other in various ways. It could be nipping each other’s fins, biting, or simply chasing each other around. In some cases, the weaker male loses the fight and dies within minutes.

Besides, fish with open wounds are more prone to disease. Consequently, injured swordtail’s health sufferers and their lives are compromised.


Male swordtails will almost certainly fight over food, which is also a form of bullying.

The stronger male will get into a fight with the weaker one and end up eating his food. As a result, the weaker male will have a poor diet and eventually starve.


A hostile environment will create a stressful environment for both male and female swordtails. Bullying, combined with starvation, will put stress and strain on weaker fish. Loss of color will expose how stressed they are.

Male swordtails do have a fantastic shape, so it’s understandable if you wanted to keep more of them. That’s possible, but only if you decide to invest in a larger tank.

To keep male swordtails from fighting in the presence of females:

  1. Purchase at least a 50-gallon tank
  2. Place two to three females for each male
  3. Create safe hiding spots by adding lots of plants and decorations

Another option is to have a male-only tank with no females. This “men’s club” will reduce their hostility, especially if they’re a large group. Start with six and work your way up.

Having a small group of male swordtails coexisting can be risky. Their compatibility will depend on their personality and level of aggression.

What to Consider When Keeping a Swordtail

Before getting a fish, make sure you read up on how to care for it. Thankfully, swordtails don’t have many requirements. They’re incredibly versatile and easy to care for.

Before you keep a swordtail buddy, consider the following three factors:

Tank size

You’re on the right track if you bought the 29-gallon tank; don’t go for something smaller.

Swordtails are community fish that thrive in large groups. That’s why smaller tanks don’t work well with swordtails.

It’s best to keep swordtails in large groups for social development. You should always consider tanks with a capacity of 20 gallons or more.

Water Parameters

They can survive in a variety of water conditions since they’re tropical fish. However, they do get comfier under certain conditions.

When it comes to temperature, they love warm water. Moreover, they thrive in alkaline and hard water.

Here are some figures to help you set up their new home:

  • Temperature: 65° – 82° F
  • PH level: 7.0 – 8.4
  • Water hardness: 12 – 35 dGH


This species, unlike bottom feeders, likes to roam around the middle and top of the tank. They’re unlikely to use any decorations at the bottom, so keep your main focus on plants.

It would be excellent if you can get live plants, as they greatly improve the water quality. Just like most freshwater fish, swordtails appreciate clean water.

Red Swordtail

What Species Can Coexist With Swordtail?

You know now that swordtails have a calm temperament, so they won’t bother their tankmates. They’ll even be on their best behavior when kept in groups.

Don’t think of keeping a single swordtail in a tank with other fish. Again, they’re community fish that thrive in groups.

When looking for a tank mate, look for species that are:

  • Similar in size to swordtail; bigger fish tend to eat smaller ones.
  • Peaceful in nature; don’t introduce aggressive species as swordtail may not be able to defend themselves.
  • Equivalent in energy level; swordtails tend to be shy if there are more active fish around

We’ve narrowed down the species that pair well with swordfish and checked all of the above points:

To Recap

The answer to how many swordtails you can keep in a 29-gallon fish tank is eight. Two males and six females, to be more specific. This ratio will limit hostility and ensure a safe environment for your fish.

Create a welcoming environment for your swordtails by following the simple guidelines shared in this article. And if you’re going to introduce new fish species to your swordtails, make sure it’s a species that’s compatible with swordtails, like platies, mollies, angelfish, and rosy barbs.

Have Another Tank Size You’re Looking for?

How Many Swordtails in a 5-Gallon Tank?

How Many Swordtails in a 10-Gallon Tank?

How Many Swordtails in a 20-Gallon Tank?