Emperor Tetra: Ultimate Guide (Care, Diet, Breeding & More)

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Written By Matt Stevens

Hi, I'm Matt! I've been obsessed with fishkeeping for over 15 years now and created this site to share my knowledge with others.

Emperor Tetra is an attractive freshwater fish that’s a mesmerizing addition to community tanks. Not only are their iridescent appearance outstanding, but they are also less demanding in captivity and ideal for novice aquarists.

As a peaceful, hardy, and active species, we can’t find many flaws in Emperor Tetras and are always surprised that these fish haven’t attracted as much attention as most Tetra species do.

Naturally, many aquarists have always preferred other Tetra species like the Cardinal and Neon varieties, failing to understand just how eye-catching their tanks would be with stunning Emperors as the center of attention.

This guide will cover the basics of Emperor Tetra care. And after reading it, you will understand what these fish prefer as the standard diet in captivity, their ideal tank size, typical behavior, best tank mates, breeding, and much more.

Species Overview

Emperor Tetras are attractive freshwater fish that are perfect for large community tanks. They are a hardy species with a peaceful temperament and an iridescent luster.

What’s more, their simple care requirements alone have turned them into a popular choice for advanced fish keepers as well as beginner aquarists.

Scientifically, Emperor Tetras are known as Nematobrycon palmeri and are part of the broader Characidae family. They are endemic to Colombia, where they roam freely in San Juan and Atrato river basins.

However, their introduction to the pet community dates back to the 1960s where they became an incredible addition to community tanks. Currently, the market is filled with captive-bred species that are just as mesmerizing as you would expect.

ColorBlue-gray, purple tones, iridescent
LifespanUp to 5 Years
Care LevelEasy
Behavior & TemperamentPeaceful
CompatibilityPeaceful, small species
Food and DietOmnivores
SizeUp to 2 Inches
Tank SetupFreshwater plants, dark substrate
Tank Size (Minimum)10 Gallons


As one would expect, the average lifespan of Emperor Tetras depends on the aquarist’s commitment to quality care and comfort. A typical species will live for about six years, but that’s never guaranteed with substandard living conditions.

Like any other species, Emperor Tetras can be vulnerable to increased stress levels, reduced water quality, and incompatible tank mates. So, you must strive to provide the best possible habitat by first understanding what to include in their territory.


Of course, Emperor Tetras aren’t the cutest freshwater Tetras in the market. However, they have distinctive features that readily set them apart from most Tetra varieties.

To begin with, these fish have beautiful slender-shaped bodies that are long and exclusively covered in blue-gray shades.

Furthermore, they display beautiful iridescent scales that are just as neat-looking as their actual bodies. A captivating purple tinge completes the base coloration and is more pronounced with reduced lighting conditions.

Next, a visible black stripe supplements the purple base coloration and extends vertically from the mouth to the tail. An up-close look reveals a small glittering blue line above the black stripe, even though this won’t be noticeable in all species.

Emperor Tetra’s fins are designed to attract your attention and will perfectly do that with distinct features like the yellow shades seen in the dorsal and anal fins, red tone towards the midsection, and a black tone at the edges.

You will easily differentiate male from female species if you look keenly. In general, male Emperor Tetras have longer bodies and take on a pointed configuration compared to the plumper females.


Emperor Tetras are a small freshwater species that only grow up to about 2 inches in full length. Therefore, they will need an even larger tank to reach about 3 inches in length.

Considering their small size, Emperor Tetras are best kept in small groups to promote efficient swimming and comfort inside the tank.

Emperor Tetra Care

Emperor Tetra care is easier than you may think and partly explains the fish’s popularity among fish lovers around the world.

As a low-maintenance species that can withstand different environmental conditions, it’s not surprising Emperor Tetras are a great choice for novice aquarists.

The next section will break down the conventional care guidelines for managing these fish at home;

Tank Size

It’s easy to assume that Emperor Tetras will thrive in a small tank just because they are a small species. But never forget that these are shoaling fish that flourish in small groups, and limiting them to a small habitat can greatly impede their health, growth, and comfort.

When designing the tank, you need to consider the total number of fish you want to keep at home, Emperor Tetra’s typical behavior, and the possible tank mates.

A small group of the same species will readily thrive in a 10-gallon tank. But because larger is always better, we recommend a 20-gallon minimum capacity to give your fish an even better experience as they explore your aquarium in unison.

The biggest mistake you could make with your Emperor Tetras is to have them overcrowded in a small tank, where they could even succumb to increasing stress levels. If it’s a community tank with multiple species, you can’t go wrong with a 30-gallon tank.

Water Parameters

Emperor Tetras are a hardy species in the wild. And, the safest approach to take to maintain their resilience in captivity is to recreate the exact living conditions in such environments.

This means the water temperature, pH levels, and water hardness must stay within the recommended levels.

And here’s how to replicate that;

  • Water Temperature: 73°F-81°F
  • Water Hardness: 3-8 dKH
  • pH Levels: 5.0-7.8

Normally, we recommend frequent monitoring of the tank water status to ensure everything stays within the recommended range.

Having the right aquarium testing kit at this stage could help you assess the tank water status and make lifesaving adjustments in time.

What to Put in Their Tank?

Like the actual conditions in their original habitat suggest, Emperor Tetras prefer dark waters with plenty of vegetation and low light levels.

So, in captivity, you can recreate this by first introducing a dark-colored substrate using fine sand to mimic the natural riverbeds.

Next, add enough live plants as part of the general tank décor to provide enough hiding spots and increase comfort and safety inside the aquarium. Here, a few best examples include famous floating plants like the water sprite and Java Fern.

Spread the plants evenly around the tank to create a compact aquarium but be sure to provide sufficient swimming space inside the tank.

You can incorporate other decorative elements like small rocks, plastic decorations, and driftwood to complete the tank décor.

For effective water filtration, you should invest in a high-quality hang-on back filter that can eliminate the common contaminants without risking the lives of your Emperor Tetras.

Also, the preferred filter shouldn’t create excessive pressure inside the tank because the Emperor Tetras come from slow-flowing waters in the wild with low water current. 

Common Diseases

Emperor Tetras aren’t susceptible to any specific diseases targeting their family. However, they will be affected by common freshwater ailments like gill flukes, Ich, and bacterial infections.

As the name suggests, gill fluke is a parasitic infection targeting the fish’s gills. Its symptoms include clamped fins and a mucus layer on the fish’s skin and can be fatal without timely intervention.

On the other hand, Ich is also caused by a parasite but, unlike the gill flukes, causes visible white spots on the fish’s body and gills.

Its highly contagious nature makes it a real menace to the freshwater fish, and you must isolate the diseased species as fast as possible to control its spread. Thankfully, you can treat it with common copper-based medications.

Other fungal and bacterial infections affecting the Emperor Tetras are linked to reduced tank water quality. They may present with small growths over the fish’s body, reduced activity levels inside the tank, or swollen bellies.

The best part about keeping Emperor Tetras is that most of these conditions are easily avoidable with ideal tank water conditions.

In many cases, the bothersome parasitic, bacterial, and fungal infections will automatically go away if you address the actual living conditions. This includes the fish’s diet, possible tank mates, and tank water quality.

What Do Emperor Tetras Eat?

Emperor Tetras are true omnivores and very easy to feed in captivity. They have a strong liking for larvae, small crustaceans, and worms in the wild.

They feed on high-quality flakes and pellets in captivity, but you can supplement their meals with high-quality protein-rich foods such as brine shrimp, daphnia, tubifex worms, and bloodworms.

Behavior & Temperament

Emperor Tetras are peaceful fish that get along with most freshwater fish with similar traits. They are not true bottom-dwelling species, even though you may occasionally spot them in the lower sections. Usually, they prefer to occupy the middle and topmost parts of the tank.

Aggression is never witnessed within an Emperor Tetra community. However, the peaceful coexistence may be threatened if you keep these fish in a small tank.

In that case, dominance will automatically set in, and the male species will be slightly aggressive as they fight for territorial control. But even then, such fights are never dangerous and shouldn’t bother you if you keep Emperor Tetras.

Most importantly, be sure to keep these fish in large tanks and remove the potential aggressors as soon as you spot them.

Emperor Tetra Tank Mates

As a general guideline, never forget that Emperor Tetras flourish in groups of 5 to 6 species. Therefore, to counter the possible aggression from the territorial males, you can limit the male’s number to just one species in the whole group.

Sometimes, aquarists prefer to keep Emperor Tetras in single pairs, which is good enough if you have a few species in captivity.

That being said, here are some of the potential tank mates worth keeping with Emperor Tetras;


Breeding Emperor Tetras in captivity is only possible if you can commit to providing the best possible conditions. For a start, you will need a separate tank to induce the process and ensure the adult fish are well taken care of during this period.

Before breeding commences, ensure the new tank has enough plants and spawning mops to protect the eggs during fertilization.

Then, adjust the water temperatures to about 80°F-82°F. Also, a neutral pH of around 7.0 would be perfect for the spawning process, with standard filters to control the ammonia and nitrate levels. 

The last week preceding the spawning period will be key to successful breeding. Therefore, you should give your fish plenty of live foods during this period before pairing them up in the new tank.

Unfortunately, Emperor Tetras have a notorious trait of feeding on the new fry in captivity. And you must avoid that by taking them out of the tank as soon as fertilization occurs.

The eggs will take a maximum of 3 days to hatch, after which the baby fish will be glad to feed on egg sacs for a few weeks.

Later, you can introduce them to infusoria as you monitor their growth rate. If they are in perfect health, they should be ready to accept baby brine shrimp and powdered food as soon as they’ve learned swimming.

Final Thoughts

Caring for Emperor Tetras is just as easy as managing other freshwater Tetras. And by now, you may be convinced that these beautiful Tetra varieties are the perfect pets for your aquarium.

Before visiting the local pet store, ensure you have everything in place to keep thriving Emperor Tetras. As you can see, security matters to these fish just as much as comfort, and the easiest way to achieve that is to create an impeccable habitat.

If the mix of peaceful temperament and natural beauty appeals to you, there could be no better time to invest in the fun-loving Emperor Tetras.