How Many Black Skirt Tetra Can I Keep In 10, 20, 30 Gallon Tanks?

There are a lot of things to think about before you purchase black skirt tetras, but the most important thing is how many can you keep in your tank without trouble. The black skirt tetra is a popular fish that can be found in 10, 20, and 30-gallon tanks. The number of black skirt tetras you should keep depends on the tank size. In this post, we will discuss how to calculate the number of black skirt tetra for a fish tank as well as other things to consider before keeping them in your aquarium.

The general rule for keeping black skirt tetra is that they should have at least five gallons per fish. If they don’t have enough space, they will become stressed and lose their coloration. In addition, if there are too many in the tank, it could lead to aggressive behavior from some or all of them.

How to Calculate the Number of Black Skirt Tetra for a Fish Tank?

To calculate the number of black skirt tetra for a fish tank, you need to know the size of the tank in gallons. For every inch of fish, you can have up to .33 gallons of water. So if you have a 20-inch fish, you can have up to six and a half gallons of water (20 inches x .33 gallons = six and a half gallons). This means you can have up to 20 black skirts tetra is a 20-gallon tank.

If you have a 30-inch fish, you can have up to ten gallons of water (30 inches x .33 gallons = ten gallons). So if you want to keep more than 20 black skirt tetra, you will need a bigger tank.

How Many Black Skirt Tetra Can I Keep In A 10 Gallon Tank?

Since a 20-inch fish can only have up to six and a half gallons of water, you can keep up to three black skirt tetra in a ten-gallon tank.

How Many Black Skirt Tetra Can I Keep In A 20 Gallon Tank?

You can keep up to 12 black skirt tetras in a 20-gallon tank.

How Many Black Skirt Tetra Can I Keep In A 30 Gallon Tank?

If you have a 30-gallon tank, you can keep up to 18 black skirt tetra without trouble.

Things To Keep In Mind Before Keeping Black Skirt Tetra In Your Tank

When deciding whether or not to buy black skirt tetras, there are some things you should take into account first. One of the most important is the size of your tank.

As we mentioned before, they have at least five gallons per inch of fish. So if you have a ten-gallon tank, your black skirt tetras should not exceed 50 inches.

Size Of Tank

Keep in mind that the bigger the tank, the more decorations, and plants it can house. This is especially important for male black skirt tetra because they are less aggressive when their territories are well established.

Just make sure there aren’t too many decorations to where the fish can get lost or trapped within them.


Decorations also affect how much light reaches into the aquarium which affects how many plants will be able to survive in each tank.

It’s best if you limit yourself to one plant per five gallons of water since some species require higher levels of lighting than others do (and those with low needs don’t provide enough cover for the black skirt tetras).


Different types of plants also require different levels of lighting and nutrients. This is where it helps to do your research beforehand so you know what kind will be able to survive in your tank, and which ones won’t work as well with your fish’s needs.

If there are too many or not enough plants for them, this could lead to stress among the black skirt tetra (or cause some other problems within the environment).

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Black Skirt Tetra Tank Size & Gender

Male Black Skirts Tetra tend to swim around a lot more than female black skirts tetra. However, male black skirts tetras need larger territories because they’re much more aggressive than females toward each other when establishing their territory.

What Happens If You Put Too Many Black Skirt Tetra In A Tank?

If you put too many black skirt tetras in a tank, this could lead to stress which will affect their coloration and behavior.

They can also become aggressive toward each other if there are not enough hiding spots for them to take refuge when they need it. This usually happens with tanks that have low water levels or weaker lighting conditions (although stronger light is necessary for plants).

Can You Overstock Your Black Skirt Tetra Tank Without Trouble?

You can overstock your black skirts tetra tank without trouble as long as the decorations provide plenty of covers and the temperature stays between 72-81 Fahrenheit during summer months and 68-75 degrees Fahrenheit during winter months.


Below are some frequently asked questions about black skirt tetra:

How big do they get?

They can grow up to six inches in length, but most will only reach around four or five inches long.

What is the ideal tank size for them?

The ideal tank size would be at least 20 gallons, with 30-50 being better.

Can I keep more than one male in a tank?

No – you should only have one male per ten gallons of water.

What kind of tank mates can I keep them with?

You can keep black skirt tetras with most other fish species, but they should not be kept in tanks smaller than five gallons.

Why does Black Skirt Tetra Lose Their Color?

While this isn’t usually dangerous for their health or the environment, it is quite frustrating to watch your beautiful male go from a vibrant green/blue color to almost completely transparent. To make sure this doesn’t happen again you’ll need to fix whatever caused their colors to fade (usually poor water quality or stress).


As long as you are careful about choosing what decorations and plants will work best within your tank’s size, lighting conditions, etc., then keeping black skirts tetra can be a very rewarding experience. Just make sure to keep an eye on their behavior and coloration so you can address any problems right away. Thanks for reading!

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