How Many Neon Tetras In A 20 Gallon Tank? All You Need To Know

Do you have a 20 Gallon Tank that you want to keep Neon Tetras in and are wondering – How Many Neon Tetras In A 20 Gallon Tank? Well, I will help you figure out the answer to this query. Keep reading.

About Neon Tetras: A Quick Overview

The sturdy little neon tetra fish, the bright crown jewel of aquariums everywhere, was originally imported from South America. Because of their popularity, Hong Kong, Singapore, and Thailand have robust captive breeding industries.

Each month, the United States imports more than 1.5 million neon tetras. Wild-caught neon tetras from South America account for less than 5% of neon tetras sold for aquariums.

Origins and Dispersal

Neon tetras are native to the Orinoco and Amazon river basins in Brazil, Columbia, and Peru, where they can be found in clear and blackwater streams and tributaries.

These are areas where blackwaters flow beneath the dense forest canopy, allowing only a small amount of light to pass through. Neon tetras eat on worms and tiny crustaceans and reside in shoals primarily in the intermediate water levels.

The majority of neon tetras are captive-bred, with the majority hailing from the Far East and Eastern Europe. There are now a variety of captive-bred species available.

These include the long-finned neon tetra, which is extremely unusual, as well as a golden neon tetra, which is essentially a semi-albino variant, and a diamond neon tetra with metallic scales sprinkled throughout the upper half of the body.

Colors and Symbols

The neon tetra has a slender, torpedo-shaped body that is just about an inch and a half long. This beautiful fish makes up for its lack of size with color.

The neon tetra has a brilliant neon blue stripe running from the tip of its nose to its adipose fin. This bright stripe is thought to make them more visible to each other in low-light situations.

how many neon tetras in a 20 gallon tank

The neon tetra has a white-silver belly beneath the blue line. A vivid red stripe runs from the belly button to the tail. The neon tetra is one of the most popular aquarium fish due to its eye-catching red, white, and blue color scheme.

It is only surpassed by its cousin, the cardinal tetra, which it is frequently confused with. The red stripe is the main distinction between the two fish.

It only extends from the middle of the body to the tail in neon tetras. The red stripe extends the entire length of the cardinal tetra, from snout to tail.

The neon tetra’s dazzling colors diminish at night, when it is resting, disturbed, or ill, just like other colorful fish. Choose lively and vibrantly colored specimens in the pet store, as faded colors can indicate poor health.


These fishes should always be kept in groups of at least a half-dozen, as they are a shoaling species that require the company of other neon tetras. In a community tank, neon tetras do well as long as the other species are neither huge nor aggressive.

Little, peaceful fish like rasboras, small tetras, dwarf gouramis, cory, and other small catfish make excellent companions. Larger tetras should be avoided since they will consume neon tetras at the first opportunity.

The general rule is that if the fish’s mouth opens wide enough to swallow the neon, they will swallow it sooner or later.

Neon Tetra Care and Habitat

Neon tetras should not be kept in newly set up tanks since they will not tolerate changes during the starting process. When your tank is fully developed, and your water chemistry is stable, add neon tetras.

For neon tetras, water should be soft and acidic, with a pH of no more than 7.0 and a hardness of no more than ten dGH. Blackwater extracts or driftwood are frequently employed to darken the water, maintain an acidic pH, and soften it.

Neon tetras reside in dark water with extensive vegetation and roots in their natural habitat. It’s critical to provide a habitat with plenty of low-light hiding spots. Provide them with as many plants as possible, including floating plants if possible.

Driftwood can also be used as a hiding place. The dark substrate will closely resemble the neon tetras’ native home. Some fishkeepers would use a dark background on three sides of the aquarium to attain the ideal low-light habitat.

Diet & Feeding of Neon Tetra

The neon tetra is an omnivore, which means it eats both plant and animal matter.

Food options include fine flake food, small granules, live or frozen brine shrimp or daphnia, and frozen or freeze-dried bloodworms. To maintain excellent health, provide a variety of foods, especially live foods.

How Many Neon Tetra Fish Per Gallon?

Are you aware of the one-inch-per-gallon guideline in fishkeeping? One gallon of water is required for each inch of fish in the aquarium. This restriction only applies to little fish under the size of 3 inches.

Neon Tetra Care

Keep in mind that the guideline does not always apply to larger fish like Oscars or Goldfish. So you can keep one neon tetra fish in two gallons of water, albeit this isn’t optimal for keeping just one neon tetra.

How Many Neon Tetras In a 20 Gallon Tank?

You must consider the size of your neon tetra fish while talking about a 20-gallon tank. Depending on your preferences and experience, you can keep 10 to 13 neon tetras in a 20-gallon tank, according to the rule of thumb.

Start with the 20-gallon tank if you expect to keep more than six neon tetras in the tank. It’ll be great for neon tetras and other small schooling but active-swimming fish.

We’ll use the same rule to establish the number of neon tetras you can keep in the tank, as you may have heard about the one-inch one-gallon rule in fish keeping. As a result, we’ll use this rule to determine how many neon tetras to keep in a 20-gallon tank.

To begin with, a neon tetra can grow up to 2 inches in length. A neon tetra typically grows to be 1.75 inches long. But, for a 20-gallon tank, let’s estimate the size of neon tetras in whole numbers.

So, if a neon tetra can grow to be 2 inches long, a 20-gallon tank can hold 20/2, or 10 tetras, according to my calculations.

What Tank Size Does Neon Tetra Need?

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The tank size you will need for neon tetras is determined by how many neons you plan to keep. The smallest tank that neons may be kept in is 10 gallons.

If you want to keep the minimum recommended number of tetras, which is 15, you’ll need a tank that’s at least 20 gallons or more.

Why Do Neon Tetras Need To Be In Groups?

For the most part, Neon Tetras get along with any other non-aggressive fish in a community tank. This means African Cichlids and Bettas aren’t a good match for each other.

Even if you’ve paired them with non-aggressive fish, be sure your tankmates aren’t too big to devour them! Because of their vivid colors and small stature, larger fish may mistake them for food rather than pals.

Neon Tetra

For Neon Tetra Tanks, Rasboras, Barbs, and Dwarf Gouramis are fantastic choices. Pairing them with fish that occupy other areas of the tank is a smart idea. Bottom-dwellers, such as little catfish, will have little interaction with the fish.

While any calm fish will get along with Neon Tetras, adding fish of the same species is always the best bet. It’s best to maintain a group of at least 15 Neon Tetras together so they can rely on one another as they would in the wild.

What Happens If I Overcrowd My 20-Gallon Neon Tetra Tank?

When your fish display signs of stress, aggression, toxicity, or a lack of oxygen, you know your tank is overloaded. Overcrowding generates stress reactions in fish, slowing their growth, decreasing their immunity, and making them more susceptible to disease.

Rehome some of the fish or purchase a larger tank to alleviate overpopulation. An overloaded tank is not only harmful to your fish’s health; it is also cruel to the fish in your care.

How to Keep Neon Tetras In A 20 Gallon Aquarium?

Beginners may find it strange that 20-gallon aquariums are claimed to be more difficult to maintain than larger tanks by more experienced aquarium owners. The reason for this is that you must create a more cautious balance. There isn’t as much space for error.

Still, if you want to experiment with tiny tanks or have previously had experience with a 20-gallon tank, you might have 15-25 tetras in your 20-gallon tank if you consider the following:

  • You can’t give your fish too much food.
  • To help with oxygen, you’ll need a lot of real plants.
  • You’ll need a water warmer as well as a filter.
  • Smaller tanks necessitate more regular cleaning.
  • Weekly water changes are required.

Can You Keep Guppies And Neon Tetras In A 20 Gallon Tank?

Guppy, Fish, Multicoloured, Colorful

YES! With appropriate conditions, guppies and neon tetras make terrific tank mates. However, if the conditions aren’t right, there could be problems in the aquarium.

You should be aware of each fish’s disposition before combining them. Knowing each fish’s temperament can help you better grasp what they require in the aquarium to stay happy.

Temperament of Guppy

Guppies are gentle fish that will not cause any problems in your aquarium. In fact, depending on their tank mates, they may be targeted from time to time. After all, fin nippers are attracted to their long tails.

Guppy, Fish, Aquarium, Freshwater

While aggression towards other fish is relatively unusual, male guppies can be aggressive between themselves, especially when the tank is depleted of females. To lessen the likelihood of violence, you should have one male guppy for every two females.

You should also be aware that guppies breed frequently and give live birth to their offspring. While the other fish will eat the majority of the fry in your aquarium, some may survive to adulthood.

The temperament of the Neon Tetra

Neon tetras are also gentle fish when given the correct circumstances. However, they have been known to nibble the fins of other fish in your aquarium on occasion (including guppies). When their wants aren’t addressed, this is a lot more common.

Betta Friends, The Neon Tetra - Fish Care

They have two basic requirements: to be kept in a school with at least six students and to be kept in a school with at least six students.

That they have enough space to swim (at least 15 gallons) and that they have lots of hiding spots. If you remember all of this, you’ll have happy neon tetras who will coexist quietly in your tank!

Remember that with both neon tetras and guppies, it’s critical to keep them as a school or shoal rather than keeping them individually.

Can You Keep A Single Tetra?

You can’t have just one neon tetra. Neon tetras are schooling fish that require a minimum of six individuals to form a school.

Without a partner in the tank, neon tetra will become depressed, and their immunity will deteriorate. They won’t eat adequately and will become sluggish or despondent. Your neon tetra’s body defense system may begin to malfunction as a result of this.

Neon Tetra

Your single and lonely neon tetra will die as a result of all of this. So don’t play around and offer them their desired school/family size.

In the wild, some of these groups can number in the thousands. Attempting to raise a single tetra in a fish tank will result in a stressed and susceptible fish.

Protection is provided by education. When neon tetras are kept in groups, they feel comfortable and for a good cause. When predators come upon a group of fish, they know it will be more difficult for them to pick out individual fish to attack.

Furthermore, predators may confuse a school of neon tetras for a larger fish due to their movement. When they are forced to live alone, they are unable to profit from the protective benefits of schooling.

The creatures become anxious because they no longer feel safe. Anxiety can lead to stress and despair in the future. Neon tetras that are stressed are more susceptible to illnesses. 

Giving lonely neon tetras companions is the only way to help them. Neon tetras, for the most part, like to go to school with other neon tetras.

They may, however, form groups with other species that resemble them. The cardinal tetra, for example, is as little and vividly colored as the neon tetra.

How Many Neon Tetras Should Be In A School?

Because these are schooling fish, a school of at least 6 Neon Tetras is required. It implies that the Neon Tetras like to spend their time in schools.

Where there are additional members of their kind, these fish feel more comfortable. Neon Tetras swim in schools, bringing even more color to your aquarium.

Betta Friends, The Neon Tetra - Fish Care

In other terms, the number of neon tetras you can have is determined by the size of your aquarium. A group of four fish may appear reasonable, yet it is insufficient. If you don’t have enough room, six people are the bare minimum.

If you have the space, aim for 15 to 20. To keep them, you’ll need at least 20 gallons of water. As previously stated, certain neon tetras exist in large groups in the wild, with thousands of members.

As a result, the happier the neon tetras are, the larger the group. However, you must make certain that the tank is large enough to hold the neon tetras. Many aquarists feel that 5 gallons are the smallest tank that neon tetras may be kept in.

However, it is safer to aim for 10 gallons. Maintaining a 5-gallon tank might be difficult. If you just have 5 gallons, however, you should take steps to prevent the water chemistry in the tank from drastically changing.

Weekly maintenance, employing an efficient filter, weekly water changes, reducing the amount of food you provide to the tank (to avoid the fish from producing excessive amounts of waste), and keeping a close check on the parameters are all part of this. 

Simply investing in a 55-gallon tank can save you a lot of time. Unless the aquariums in question are overstocked, the conditions in huge tanks are quite steady. In any case,

How many neon tetras are in a 20-gallon long tank? 

A school of 11 to 14 Neon Tetras can be housed in a 20-Gallon long Tank.

How many black neon tetras are in a 20-gallon tank?

Because black neon tetras are energetic swimmers, it’s best to keep 8 to 10 of them in a tank that’s at least 20 inches long and holds at least 20 gallons.

How many neon tetras are in a 20-gallon community tank?

In a twenty-gallon community tank, you can even mix fish species and keep neon tetras. That implies you can keep 5 Neon Tetras while still having room for GloFish, Endlers Guppies, Snails, Barbs, Platies, or Mollies.


Neon tetras are tranquil and lively fish that can be an excellent addition to your aquarium. They are quite hardy and do not necessitate any effort on your side. That being said, neon tetras have their own set of criteria that must be met in order for them to survive.

To begin, choose an aquarium with at least 20 gallons of space to accommodate a small group. If possible, aim for 30 gallons or more. You may have a school of over 20 neon tetras this way. The neon tetra is a very gregarious fish.


How many neon tetras are 15 gallons?

As per the rule of thumb, you can keep 15/2 inches =7.5 or 8 neon tetras in a 15-gallon tank. Furthermore, if you take care of them and maintain the water quality, you should easily fit 10 to 12 of these fish species.

How many neon tetras can I put in a 10-gallon betta?

With proper filtration and weekly partial water changes, you may comfortably keep 6–8 neons in a 10 gallon [38 liters] with one male betta.

How many Glofish Tetras can you have in a 15-gallon tank?

Glofish flourish in groups, so in a 15-gallon tank, at least 5 of the same species are advised.

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