How Many Tetras In A 30-Gallon Tank? One Inch Per Gallon?

Dec 17, 2021

How Many Tetras In A 30-Gallon Tank

I have a 30-gallon tropical fish tank with some tetras in my office. What I like about tanks this size is that there’s plenty of room to play with and make mistakes. It’s not small enough to magnify even the slightest fluctuations nor big enough to be overwhelming to maintain. If you were to keep only tetras in a 30-gallon tank, how many could you fit? How many tetras in a 30-gallon tank is doable?

Let’s find out! 

How Many Tetras In A 30-Gallon Tank?

The ‘one inch per gallon’ rule is up for debate, but it can be applied for fish smaller than 3 inches without any complications. If we were to assume the tetra’s average length is 1.75, you could fit 17 (17.14) tetras in a 30-gallon tank. 

However, note that this rule doesn’t apply to big fish like goldfish or cichlids. 

Also, this rule doesn’t take into account the fish’s height or the space taken by the substrate, decors, and plant. 

That’s why fishkeepers who use this rule tend to allocate 10 gallons separately for the area covered by substrate and decors. 

So, if you were to do so too, you’d have 20 gallons for the fish. And in 20 gallons, you can fit around 11-12 tetras. 

However, from what I read on several forums, you can pretty easily raise 35-40 tetras in a 30-gallon tank if you know how to work your way around it. 

With the help of the ‘one inch per gallon’ rule, let’s calculate the stocking number for different kinds of tetras.

Recommended Readings!

How Many Neon Tetras In A 5-Gallon Tank? Honest Answers!

How Many Tetras In A 3-Gallon Tank? Will Small Tank Stunt Growth?

How Many Neon Tetras In A 10-Gallon Tank? With Bettas And Guppies?

How Many Neon Tetras In A 30-Gallon Tank? 

Neon tetras are undoubtedly the most recognizable tetra species. Their popularity in the aquarium trade is immense. 

And these fish grow around 1.5 inches (4 cm) long on average. 

When 30 is divided by 1.5, we get 20. 

So, you can keep around 20 neon tetras in a 30-gallon tank. 

How Many Glofish Tetra In A 30-Gallon Tank? 

With proper care, glofish tetra can reach 2 inches (5 cm) in captivity. Actually, these amazing fish are genetically modified variants of the black skirt tetra. 

So, when we divide 30 by 2, we get 15. Therefore, you can comfortably house at least 15 glofish tetras in a 30-gallon tank. 

How Many Ember Tetras In A 30-Gallon Tank? 

Credits: Joachim Muller (Creative Commons license)

Ember tetras are lesser-known species that have a lot to offer to the fishkeeping hobby. Sporting a brilliant orange shade, these fish grow only 0.8 inches (2 cm) long. 

When we divide 30 by 0.8, we get 37.5!

So, yes – you can house 37-38 ember tetras in a 30-gallon tank. 

How Many Cardinal Tetras In A 30-Gallon Tank?

Cardinal tetras are often confused with neon tetras due to their physical similarities. However, the main differentiator is that cardinal tetras have a horizontal red dash across the lower body, while neon tetras only have a partial red coloration. 

These fish don’t grow too big – clocking in at around 1.25 inches (3 cm). 

And when we divide 30 by 1.25, we get exactly 24. 

Hence, you can add 24 cardinal tetras in a 30-gallon tank. 

How Many Congo Tetras In A 30-Gallon Tank?

First introduced in the fishkeeping hobby in the 1970s, congo tetras sport iridescent shades of blue, orange, gold, and violet in their body. 

These fish grow quite big for tetras – reaching 2.5 to 3 inches (6.3-8.5 cm) in length. 

Assuming the fish is 3 inches long, you can house exactly 10 of them in a 30-gallon tank. 

How Many Emperor Tetras In A 30-Gallon Tank?

Ubiquitous in rivers throughout Colombia, emperor tetras look nothing short of royalty in their deep purple bodies. 

Emperor tetras grow only over 1.6 inches (4.2 cm) long. Hence, you can add around 18-19 of these fish to a 30-gallon tank. 

How Many Buenos Aires Tetras In A 30-Gallon Tank?

Natives of Argentina, as the name suggests, Buenos Aires tetras have beautiful splashes of blue, green, yellow, and red in their bodies. 

These fish grow quite big by a tetra’s standards. They can reach 3 inches (7.6 cm) long. 

So, you can add around 10 of them in a 30-gallon tank.

How Many Lemon Tetras In A 30-Gallon Tank?

Credits: Michael Palmer (Creative Commons license)

If you’re hoping to add a splash of the brightest yellow to your tank, lemon tetras have got you covered. Although iridescent silver makes up most of their bodies, the vibrant yellow spots here and there steal the show. 

These petite fish grow around 1.5 inches (3.8 inches) long. So, when we divide 30 by 1.5, we get 20. 

Thus, we can house about 20 lemon tetras in a 30-gallon tank. 

How Many Serpae Tetras In A 30-Gallon Tank?

Serpae tetras are also known as jewel or callistus tetras. They are active fish that need a good amount of space to swim freely. 

They can reach around 2 inches (5 cm) long in captivity. 

So, we can house about 15 of them in a 30-gallon tank as 30 divided 2 is 15. 

How Many Diamond Tetras In A 30-Gallon Tank?

As the moniker suggests, diamond tetras are the shiny stars of any tank. 

Covered in ultra-shiny scales, these fish only grow around 2 inches long. 

And since 30 divided by 2 is 15, you can house 15 of these fish in a 30-gallon tank. 

How Many Black Skirt Tetras In A 30-Gallon Tank?

Credits: Jackie (Creative Commons license)

Unlike colorful tetras, black skirts sport a majestic gray and black appearance. These fish grow about 3 inches (7.6 cm) long. And when we divide 30/3, we get 10. 

Therefore, you can house 10 black skirt tetras in a 30-gallon tank. But if you are confident with your maintenance abilities, you can go a notch higher. 

These fish love to school and swim in unison. So, it will definitely be a sight to see! 

Now that I’ve covered the answer for different tetra species, let’s have a brief look at a 30-gallon tank. 

Frequently Asked Questions 

What’s A 30-Gallon Fish Tank’s Dimensions?

A 30-gallon fish tank usually has the following dimensions: 36” x 18” x 12” (L x W x H). 

How Much Does A 30-Gallon Fish Tank Weigh?

An empty 30-gallon fish tank weighs around 48 lbs. When filled with water, the weight goes up to 348 lbs. 

How Much Does A 30-Gallon Fish Tank Cost? 

The price of a fish tank mainly depends on 3 factors – the material, shape and design, and the equipment included. 

Glass tanks are more scratch-proof and heavier than acrylic tanks. You will have to pay around $300-500 on average for a 30-gallon glass fish tank. 

On the other hand, acrylic tanks are lighter and more durable than their glass counterparts. Thus, they are a bit costlier. The price can go up to $600. 

The tank’s shape and design also play a pivotal role in determining the price. 

Naturally, a simple rectangular design will be the most affordable, whereas exotic shapes like hexagons, cubes, and bow-front will cost you more. 

And the last determining factor is whether you’re buying the tank as a standalone piece or as a part of a kit. If you’re buying it as a part of the kit, expect to pay $50-150 extra for everything else that comes with the tank. 

The kit usually includes a pump, heater, lighting, and filter. 

Final Words: How Many Tetras In A 30-Gallon Tank? 

You can comfortably keep around 17-18 neon tetras in a 30-gallon tank. Even though the ‘one inch per gallon’ rule is somewhat controversial and up for debate, it can be safely applied for fish like tetras, provided that you allocate some space taken by gravel and decors. 

Relevant Readings!

How Many Angelfish In A 40-Gallon Tank? Will They School?

How Many Angelfish In A 29-Gallon Tank? Do They Shrink In Small Tank?

How Many Angelfish In A 75-Gallon Tank? Use This Golden Rule!

How Many Angelfish In A 55-Gallon Tank? Use This Formula!

How Many Cichlids In A 75-Gallon Tank? Mbunas, Peacocks And South American

How Many Cichlids in a 55-Gallon Tank? Use This Simple Formula!

How Many Cichlids In A 40-Gallon Tank? Cichlid List For A 40-Gallon Tank

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.