How Many Neon Tetras in a 20-Gallon Tank?

You can typically fit around 10 to 13 neon tetras in a 20-gallon tank. Neon tetras are a schooling type of fish, which means they can get lonely and die when tanked alone.

For this reason, if you’ve got a 20-gallon tank, try to fill it with as many neon tetras as you can keep.

Neon tetras are a calming sight to behold. Seeing a rush of blue and red in the tank brings the tropical aquarium landscape together.

The more neon tetras you can fit, the denser your aquatic jungle will be.

Stick around to learn more about the number of neon tetras you can keep within a 20-gallon tank as well as more care tips.

How Many Neon Tetras in a 20-Gallon Tank?

The number of neon tetras you decide to keep in a 20-gallon tank depends on a few key aspects.

For instance, if you’re a beginner in fishkeeping, then you may want to start with a smaller number of neon tetras such as 10 to 12.

As you advance your understanding of aquarium care, you can add in more neon tetras to accumulate over 30 fish residents.

Another factor worth considering is the tank’s size specifications. In other words, a long 20-gallon tank will fit more neon tetras comfortably than a high 20-gallon tank.

Aside from that, most tank specialists and enthusiasts may recommend the one-inch-per-gallon rule of thumb.

Group of Neon Tetras

One-Inch Per Gallon Rule

This rule stipulates that you can add an inch of fish for every gallon of water in the tank. Now, neon tetras are relatively small and slender.

Their average height can reach up to 1.5 inches. With this in mind, you’ll want to divide 20 by 1.5 which would then equal approximately 13 neon tetras in a 20-gallon container.

Although this rule has been widely used to determine how many fish to keep in a tank, it has met some criticisms. For instance, the rule doesn’t take notice of the space filled with decorations, homes, plants, and substrates.

In addition to this, the rule doesn’t take into account the fish’s height. Luckily, neon tetras are small, to begin with, so the rule may still apply to them.

Subsequently, the one-inch per gallon rule may only apply to fish that are at least smaller than three inches.

12 Square Inch Per Inch Rule

Another rule worth following is the 12 square-inch per inch rule. It takes into account the tank’s floor and surface area giving you a more accurate calculation.

To follow the rule, you first need to estimate the tank’s surface area by multiplying its length and width. For example, let’s assume you have a long 20-gallon tank that’s 30 inches long and 12 inches wide.

The surface area would then be 360. Afterward, you divide this number by 12, which will then be 30.

Next, all you have to do is divide 30 by the average height of the neon tetras. In this case, it’s 1.5 inches.

Our final answer would then be 30/1.5, which is 20 neon tetras. Now, with 20 neon tetras in a 20-gallon tank, you’ll need to provide extra care in terms of filtration and tank cleaning.

About Neon Tetras

If you’re thinking of owning neon tetras, you may want to get brief background information on the tropical fish.

That being said, this freshwater fish originated from the clearwater and blackwater streams of the Amazon basin in South America. They’re native to countries such as Brazil, Colombia, and Peru.

The fish breed is characterized by its peaceful and social temperament. They’re ideal fish to keep for beginners. Aside from that, you never want to keep a neon tetra alone. Otherwise, it may weaken and die out of loneliness.

You should at least keep six neon tetras together. Neon tetras can live with other peaceful fish as well in a tank.

Overall, the red-blue streaked fish can survive for about five years or more, depending on how well they’re taken care of.

What Happens If You Overcrowd a Tank with Neon Tetras?

Known for their peaceful disposition, neon tetras won’t particularly act out if the tank is overcrowded.

Having said that, it’s no picnic for them either. Imagine living in a small apartment with ten other people.

If you do overcrowd the tank, their excretions will increase ammonia levels in the tank. If your filtration system isn’t catching up, the tank will become a hazy mess.

Consequently, a polluted and unkempt tank will likely be fatal for your school of neon tetras. They’ll likely become suffocated in the cloudy tank, stressed, and weakened.

Apart from that, the energetic torpedo-shaped fish need their space to move around. With little space, they’ll be uncomfortable.

How Many Neon Tetras in a 10-Gallon Tank?

If you’re thinking of purchasing a smaller 10-gallon tank, you can keep around six neon tetras. This is according to the one-inch per gallon rule.

A 10-gallon six neon tetras arrangement is perfect for beginner fish keepers. It’ll be easier to filtrate the water and feed six rather than ten or more neon tetras.

How Many Neon Tetras in a 5-Gallon Tank

A five-gallon tank can hold about three neon tetras. Nonetheless, we wouldn’t recommend this arrangement since neon tetras thrive in groups comprised of six or more of their kind.
Now, despite their peaceful temperament, keeping three neon tetras will likely make them stressed. Subsequently, they’ll resort to aggressive behavior.

Have Another Tank Size You’re Looking At?

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How Many Neon Tetras in a 10 Gallon Tank?

To Conclude

How many neon tetras can you fit in a 20-gallon tank? In short, you can keep around 10 to 12 neon tetras in a single 20-gallon tank.

That being so, you can exceed this amount only if you’re an experienced fish keeper. Otherwise, overcrowding the tank without experience with filtration systems and temperature regulation could put your tetras in harm’s way.

All in all, neon tetras are hardy tropical freshwater shoaling fish that are better off in groups of six or more. With the right care requirements, they can live a healthy full life and provide you with an aesthetically colorful aquarium for years to come.