How Many Neon Tetra Can Be In A 33-Gallon Tank?

How Many Neon Tetra Can Be In A 33-Gallon Tank?

Neon tetras are one of the most popular aquarium fish due to their vibrant colors and peaceful nature. If you’re considering adding these beautiful little fish to your 33-gallon tank, you may be wondering how many of them can comfortably coexist in that space.

Well, you’ve come to the right place! In this article, we’ll guide you through the process of determining the ideal number of neon tetras for your 33-gallon tank.

Key Takeaway

To summarize the information in this article, here’s a quick reference guide:

Tank SizeRecommended Number of Neon Tetras

Now, let’s dive deeper into the factors that influence how many neon tetras can thrive in a 33-gallon tank.

Considerations for Neon Tetra Population

Before determining the number of neon tetras suitable for your 33-gallon tank, several factors need to be taken into account. These include the fish’s size, social behavior, and the need for adequate swimming space. Let’s break it down:

Size of Neon Tetras

Neon tetras are small fish, typically growing up to 1.5 inches (3.8 cm) in length. Their small size means that they don’t require a tremendous amount of space individually. However, it’s essential to consider their group behavior and provide them with enough swimming room to flourish.

Social Behavior

Neon tetras are known to be schooling fish, which means they prefer living in groups. In the wild, they form large shoals for protection and social interaction. Keeping them alone or in small numbers can lead to stress and compromised health.

Swimming Space

Neon tetras are active swimmers, and they thrive in tanks that provide ample swimming space. Crowded conditions can lead to stress, decreased water quality, and increased aggression amongst the fish. It’s vital to strike a balance between allowing them to swim freely and maintaining a suitable population size.

Determining the Number of Neon Tetras

Based on the factors mentioned above, a general guideline to follow is to include 1 inch (2.5 cm) of fish per gallon of water. Applying this guideline, for a 33-gallon tank, you can have around 20-25 neon tetras comfortably.

It’s important to note that this guideline assumes you have no other fish or large ornaments occupying space in the tank. If you have other fish or decorations, you’ll need to adjust the number of neon tetras accordingly.

Benefits of Maintaining a Suitable Population

Keeping the right number of neon tetras in your 33-gallon tank has several advantages. Here are a few:

  1. Social Interaction: Neon tetras are most comfortable when in a group. By providing them with a suitable population, you enable them to engage in their natural schooling behavior.

  2. Reduced Stress: A well-balanced population ensures that each fish has enough space, reducing stress levels and promoting better overall fish health.

  3. Water Quality: With fewer fish, it’s easier to maintain good water quality. The more fish you have, the more waste they produce, which can lead to water pollution and health issues.

  4. Brighter Colors: When neon tetras are kept in an appropriate number, they tend to exhibit more vibrant colors. A happy and healthy school of neon tetras can truly enhance the visual appeal of your tank.


In a 33-gallon tank, a population of 20-25 neon tetras strikes a good balance between providing them with a suitable environment to thrive while maintaining water quality. Remember, these guidelines are just a starting point, and it’s always important to monitor the behavior and well-being of your fish.

With this information in hand, you’re well-equipped to create a beautiful and harmonious home for these mesmerizing neon tetras. Happy fish keeping!