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How Many Neon Tetras In A 55-Gallon Tank?

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If you own a 55-gallon tank and wonder how many neon tetras you can keep together in there, you have come to the right place.

Here, I’ll discuss the right numbers, explain how the calculation is made, and offer some suggestions on mixing some other types of fish in your 55-gallon neon tetras tank.

Let’s dive right in.

How Many Neon Tetras Can You Keep In A 55-Gallon Tank?

Approximately 30 to 35 neon tetras can comfortably live in a 55-gallon tank.

This calculation is based on the guideline of one inch of fish per gallon of water, considering that a fully grown neon tetra measures around 1.5 inches.

How To Calculate The Number Of Neon Tetras In A 55-Gallon Tank

Here is how I calculated the estimated range of 30 to 35 neon tetras in a 55-gallon tank, following the one-inch-per-gallon rule:

  • Determine the mature size of the neon tetra, which is commonly around 1.5 inches.
  • Employ the widely acknowledged guideline proposing one inch of fish per gallon of water.
  • Divide the tank capacity of 55 gallons by the fish size of 1.5 inches.
  • The outcome is approximately 36, but for the well-being and contentment of the fish, it is recommended to round down.
  • Consequently, a 55-gallon tank can comfortably house approximately 30-35 neon tetras.

Why A 55-Gallon Tank Is Excellent For Neon Tetras

If you own a tank of 55 gallons, it’s great news, and this is why:

  • Space for Schooling: Neon tetras are schooling fish, and a 55-gallon tank allows a healthy-sized school, supporting their social behavior and reducing stress.
  • Stability of Water Parameters: A larger tank, such as a 55-gallon one, helps maintain water parameters more stably, promoting healthier living conditions for the fish.
  • More Swimming Space: The size of a 55-gallon tank provides ample swimming space for neon tetras, promoting exercise and overall well-being.
  • Enrichment Opportunities: A larger tank allows for more opportunities to add plants and hiding spots, creating a more enriched, naturalistic environment for the neon tetras.
  • Disease Prevention: Larger tanks like a 55-gallon tank can help prevent the spread of disease among fish, as the increased water volume dilutes potential pathogens and toxins.
  • Greater Visual Impact: A 55-gallon tank can house a larger school of neon tetras, which not only benefits the fish but also creates a more visually stunning spectacle for observers with their vibrant colors and synchronized swimming patterns.

Also Read: Neon Tetra Tank Size

Tips For Successfully Raising Neon Tetras In A 55-Gallon Tank

Keeping neon tetras in 55 gallons isn’t that difficult, but I still recommend following a few ground rules:

  • Create Ideal Water Conditions: Make sure to maintain a suitable water temperature for neon tetras, ranging between 70°F and 81°F (21°C and 27°C). The pH should ideally be kept between 6.0 and 7.0.
  • Provide Adequate Lighting: Neon tetras are native to shaded areas and murky waters, so they prefer subdued lighting. A balance of light and dark periods mimics their natural environment and is key for their wellbeing.
  • Ensure Good Filtration: A good quality filter that can handle the capacity of a 55-gallon tank is essential to remove toxins and maintain clean water for the fish.
  • Create Schools: Neon tetras are schooling fish. Aim for a group of at least 15 neon tetras to replicate their natural social structures and reduce stress.
  • Enrich the Environment: Neon tetras prefer a habitat with a lot of plants and hiding spots. Use live or artificial plants and decor to mimic their natural environment in the Amazon River.
  • Feed a Balanced Diet: Feed your neon tetras a varied diet, including high-quality flake food, micro-pellets, and occasional treats like brine shrimp or blood worms, to ensure they get all the nutrients they need.

Also Read: How Many Neon Tetras In A 40-Gallon Tank?

Does The Gender Of Neon Tetras Affect Their Population In A 55-Gallon Tank?

The gender of neon tetras does not impact their population in a 55-gallon tank.

Male and female neon tetras exhibit similar size and behavior, and there are no significant differences between them that would affect the number of tetras that can comfortably inhabit a 55-gallon tank.

Will A 55-Gallon Tank Become Overcrowded Due To Neon Tetra Breeding?

Although neon tetras can breed within a 55-gallon tank, the likelihood of overcrowding due to breeding is low.

Neon tetras are not known to be prolific breeders in home aquariums, as successful breeding requires specific conditions.

Even when breeding does occur, many of the eggs and fry often fail to survive without special care.

Is Breeding Neon Tetras Possible In A 55-Gallon Setup?

Yes, breeding neon tetras is possible in a 55-gallon setup. However, creating optimal conditions for breeding is vital to increase the likelihood of successful reproduction:

  • Create a Breeding Tank: It’s often best to set up a separate breeding tank for neon tetras to control the environment better and protect the eggs and fry from other fish.
  • Ideal Water Conditions: Adjust the water parameters to encourage breeding. For spawning, neon tetras prefer water that is slightly acidic and softer, with a pH range of 5.0 to 6.0. Moreover, I recommend keeping the temperature slightly higher at around 80°F (27°C).
  • Condition the Fish: Feed the neon tetras a high-quality diet rich in protein, such as brine shrimp and bloodworms, to condition them for breeding. Typically, after 1-2 weeks of this diet, females will become noticeably rounder when they are ready to spawn.
  • Provide Cover: Neon tetras scatter their eggs, so provide plenty of plants or a spawning mop in the tank. These will catch the eggs and offer some protection from potential egg-eating adults.
  • Lighting Conditions: Neon tetras prefer to spawn at dawn, so simulate these conditions with a dim light in the breeding tank.

How Often Do Neon Tetra Breed?

Neon tetras can breed every 1-2 weeks under ideal conditions in a 55-gallon tank.

However, this frequency can be variable and largely depends on the conditions provided, such as the right water parameters and diet.

It’s worth noting that neon tetras aren’t known for being prolific breeders in home aquariums without specific care.

Can You Add More Neon Tetras To A 55-Gallon Tank?

Yes, you can add more neon tetras to a 55-gallon tank, as long as you respect the maximum capacity. Here are some tips to ensure a successful introduction:

  • Consider Tank Capacity: Always consider the one-inch per-gallon rule. With neon tetras typically reaching 1.5 inches, a 55-gallon tank can comfortably accommodate approximately 30-35 tetras.
  • Add in Groups: Neon tetras are schooling fish and feel safer in numbers. Try to add them in groups, ideally of at least 6 at a time.
  • Quarantine New Fish: It’s essential to quarantine new neon tetras for around 2-4 weeks before introducing them to the main tank to prevent the spread of potential diseases.
  • Perform Regular Water Changes: Maintain regular water changes in the main tank, ideally, around 20% to 30% every week, to ensure optimal water quality and reduce stress on both the new and existing fish.
  • Match Water Parameters: Ensure the water parameters in the quarantine tank and the main tank are similar to make the transition easier for the new neon tetras.
  • Use Drip Acclimation: When moving the new tetras from the quarantine tank to the main tank, use a drip acclimation process over a period of about an hour to avoid shock from sudden changes in water parameters.
  • Monitor the Fish: Keep an eye on both the new and existing fish for signs of stress or disease. If any issues arise, address them promptly to maintain a healthy aquarium.

What Is The Minimum Number Of Neon Tetras For A 55-Gallon Tank?

The minimum number of neon tetras for a 55-gallon tank should be six, as neon tetras are schooling fish and they thrive better in groups.

However, given the size of a 55-gallon tank, a larger school of at least 15-20 neon tetras is often recommended for optimal social interaction and overall well-being.

Keeping Neon Tetras With Other Fish In A 55-Gallon Tank

If you’re considering mixing a group of neon tetras with other fish species, here is a helpful table I’ve compiled highlighting some commonly compatible species:

Fish CombinationQuantity of Fish (in 55 gallons)
Neon Tetras (alone)30-35
Neon Tetras & Guppies20 Neon Tetras, 15 Guppies
Neon Tetras & Mollies20 Neon Tetras, 10-12 Mollies
Neon Tetras & Zebra Danios20 Neon Tetras, 20 Zebra Danios
Neon Tetras & Platy Fish20 Neon Tetras, 15 Platy Fish
Neon Tetras & Betta Fish20 Neon Tetras, 1 Betta Fish

1. Neon Tetras And Guppies

You could comfortably house around 20 neon tetras and 15 guppies in a 55-gallon tank. 

Both species are small, peaceful, and prefer to live in groups, so they should cohabitate peacefully.

The larger space of a 55-gallon tank also helps to reduce the likelihood of any territorial disputes.

2. Neon Tetras And Mollies

A mix of around 20 neon tetras and 10-12 mollies could be suitable for a 55-gallon tank.

This accounts for the fact that mollies are slightly larger and need a bit more space. Both species are generally peaceful, making them compatible tank mates.

3. Neon Tetras And Zebra Danios

You might keep approximately 20 of each species in a 55-gallon tank.

Both neon tetras and zebra danios are similarly sized, active, and prefer to be in schools. The larger tank allows for enough space for both schools to swim freely.

4. Neon Tetras And Platy Fish

A 55-gallon tank could accommodate around 20 neon tetras and 15 platy fish.

Platy fish are slightly larger than neon tetras, and this combination allows each species enough space to thrive while ensuring the tank doesn’t become overcrowded.

5. Neon Tetras And Betta Fish

You could comfortably house around 20 neon tetras and one betta fish in a 55-gallon tank. Betta fish can be territorial and should generally be kept singly.

The neon tetras are small and peaceful enough not to threaten the betta, while the larger tank size can help prevent the betta from becoming overly territorial.


A 55-gallon tank can easily hold 30-35 neon tetras. It will be pretty easy to maintain stable water parameters within that tank size.

However, if you wish to add more tetras or mix some other fish, lower the numbers a bit, as I discussed earlier. Make sure to perform regular water changes and test the water regularly.