Freshwater Fish

Emperor Tetra – Nematobrycon palmeri: the complete care guide

The Emperor Tetra is an underrated freshwater fish that we have been fans of for years. While they are not as popular as some of the other tetras, we think they deserve more attention.

These fish have an understated beauty that really shines when you see them in person. Not only that, they are also extremely easy to care for!

This guide will teach you the basics of Emperor Tetra care and give you lots of additional information you should know if you’re thinking of becoming an owner. When you’re done reading it, you’ll be ready to buy it yourself!

Species Summary

Emperor Tetras (scientific name: Nematobrycon palmeri) are popular freshwater fish that you will often find in larger community tanks. Revered for their peaceful attitudes and relatively easy care requirements, these fish are ideal for beginners and beginners alike.

In the wild, the Emperor Tetras can be found throughout Colombia. They are most commonly found in the Atrato and San Juan river basins.

First introduced to the aquarium trade in 1960, the Emperor Tetras have become a staple in the community. These fish are bred in large numbers throughout the world and are readily available at many pet stores.

While not the flashiest species in the Tetra family, Emperor Tetras have a unique look that will definitely stand out in the right setting.

Average size of the Emperor Tetra

The average size of the adult Emperor Tetra is only about two inches long, making this a fairly small freshwater species.

Some owners have reported lengths closer to three inches, but that’s usually only possible when kept in very large tanks (and even then it’s not a guarantee). Most will stay at the smaller size in a captive tank regardless.

Author’s Note: Due to their small size, Emperor Tetras are often kept in groups. While not true school or school fish, these Tetras have been known to swim in unison when kept in large numbers.

Life expectancy

The average life expectancy of an Emperor Tetra is approximately six years with proper care.

Like any other species of fish, an Emperor Tetra’s lifespan is directly affected by the level of care it receives. Fish kept in poor water conditions are highly prone to stress and disease, so it is important to pay attention to their needs and provide them with the best possible care.

It’s also smart to buy fish from a reputable seller. This will lessen the chance that you will purchase a fish that has underlying health issues or genetic conditions.


Emperor Tetras are beautiful fish with several defining characteristics. The shape of the fish is elongated and slender. The primary color is bluish gray.

However, the scales of this species have a unique iridescent quality. The purple undertones create a beautiful glow. The purple tones are much more apparent in low light conditions.

Accompanying that base color is a prominent black stripe. It goes from the mouth to the tip of the tail! If you look closely you might also see a small bright blue line directly on top of the black stripe with some fish.

The fins also have some subtle details. Most specimens have a little yellow on the anal and dorsal fins. This may be accompanied by a red tint where the fin meets the body, as well as a black outline on the edge.

Emperor Tetras are very sexually dimorphic, which makes it very easy to distinguish between males and females. Males tend to be slightly longer and take on a more pointed shape. Meanwhile, the females have a plumper body.

Thats not all. Males and females also have different colored eyes! Females typically have metallic green eyes, while males have metallic blue eyes.

Finally, there is the tail. Males have a prominent ray in the center of the caudal fin. At first, it appears to be an extension of that black stripe on the body. However, it extends beyond the center point, resulting in a characteristic trident shape.

Emperor Tetra Care

Emperor Tetra care is very simple, which is one of the main reasons they are so popular with aquarists.

This means that they are not only beautiful, but require very little maintenance. These fish are hardy and generally undemanding when it comes to food.

Emperor Tetras are tropical species that thrive in typical freshwater conditions. However, that doesn’t mean you should take care of them lightly. Here are some established care guidelines that you should follow to keep your fish healthy.

tank size

Ultimately, the best aquarium size for your fish will depend on a number of factors. As we mentioned earlier, Emperor Tetras are perfect for larger community tanks.

Because of this, you will need to consider the entire size of the community when choosing an aquarium.

If you have a single species tank, a small group will work well in a small 10 gallon tank. 20 gallons is even better if you want to hold a large group.

Author’s Note: These fish need a lot of room to swim, so it’s important not to overcrowd a smaller tank.

For community tanks with other species, a minimum aquarium volume of 30 gallons is recommended.

water parameters

The best way to keep Emperor Tetras healthy is to replicate water conditions in the wild. Fortunately, that’s pretty easy to do in most homes!

In nature, these fish live in slow currents. The water is warm and moderately hard.

  • Water temperature: 73°F to 81°F (middle of this range is best)
  • pH levels: 5.0 to 7.8
  • Water hardness: 3 to 8 dKH

While Emperor Tetra can adapt to a wide range of conditions, it’s best to keep things as stable as possible. These fish can react negatively to extreme water changes.

That makes it crucial to perform regular water changes and equip the tank with a powerful filtration system that can keep ammonia levels low.

What to put in your tank

If you were to take a trip to South America and take a look at the natural habitat of the Emperor Tetra, you would notice that the waters are dark and full of vegetation.

Due to those environmental characteristics, these fish prefer dim lighting with plenty of places to hide.

Start with a dark colored substrate at the bottom of the tank. You can use gravel. However, the dark colored sand is closer to what is found in natural riverbeds.

Incorporate live plants throughout the tank. These plants will serve as hiding places, places of exploration and refuge from light. You can add floating plants with tons of leaves. Java fern and water sprite are good options.

Arrange the plants around the tank. But make sure there is enough room to swim without the fish getting entangled in the leaves.

On the substrate, you can also implement decorations. You can use items like driftwood, rocks, and even plastic tank decorations.

Author’s Note: For tank equipment, you will need a low wattage light and a suitable filter. A reliable backup filtration system should work just fine.

However, you must ensure that the water outlet of the filter does not generate too much flow. Place plants or decorations to lessen water disturbance if necessary.

Possible common diseases

No diseases are known to affect the Emperor Tetra species as a whole. However, they can still experience a variety of common freshwater fish diseases. Some of the most common are Ich, gill flukes, and various infections.

Ich is a parasitic disease that manifests itself through white spots all over the body. It is highly contagious and can spread rapidly in the closed ecosystem. Fortunately, it is easy to treat with copper-based medications.

Gill flukes are another parasite that can affect Emperor Tetras. It sticks to the gills. It causes a noticeable infection and has the potential to be fatal if not addressed quickly.

Finally, there are bacterial and fungal infections. These ailments can lead to unwanted growth on the body or visible rashes.

The good news is that all of these diseases are preventable. In most cases, health problems are directly caused by poor living conditions and stress. As long as you maintain your tank, you shouldn’t run into too many problems.

Food and Diet

Emperor Tetras are very easy to please when it comes to food. They readily accept commercial fish flakes or pellets.

These fish are omnivores. In the wild, they typically feed on worms, larvae, and small crustaceans. You can provide an occasional high-protein snack along with dry foods.

Daphnia, brine shrimp, freeze-dried bloodworms, and Tubifex are good choices.

behavior and temperament

Peaceful in nature, the Emperor Tetras get along with most non-aggressive fish.

They will generally stay towards the middle and top of the water column. However, they may venture to the bottom from time to time.

Acts of aggression do not occur frequently with this species, but when they do, it usually occurs with males. Males tend to fight for dominance in smaller tanks.

Usually this fight does not result in significant bodily harm, but it is still important to keep an eye on the fish and take out the aggressors separately.

tank mates

Emperor Tetras do best in groups of five or six fish. Due to the aforementioned aggression between males, it is wise to keep only one male in the group. This prevents any fighting and keeps the community in peace.

If you don’t want to keep a large group, these fish also do well in a simple close-knit pair.

As for other species of fish to consider as tank mates, you are spoiled for choice. For the most part, any similarly sized Pacific fish will work just fine.

Ideally, you’ll want to stay with tank mates that hail from South America and have similar habitat preferences. It is also important to avoid larger fish that could mistake the Emperor Tetra for food.

Here are some tankmates worth considering:

  • Ember Tetra
  • Danio Celestial Pearl
  • gourami pearl
  • cory catfish
  • pencil fish
  • gourami honey
  • serpae tetra
  • sparkling gourami
  • Apistogramma
  • guppies
  • plates
  • dwarf gourami

Author’s Note: Emperor Tetras can also co-exist with most freshwater aquarium snails.


Breeding often occurs without any intervention if the fish are kept in an optimal environment. However, you can also activate the process.

To do so, you will need to create a separate breeding tank.

The tank should have higher temperatures around 80 to 82 degrees Fahrenheit. The water should be on the softer side and have a pH balance of around 7.0. Use a filter equipped with sponges to prevent damage to baby fish.

Introduce plenty of plants into the breeding tank. They will play an important role in protecting the eggs. Emperor Tetras are known to eat eggs, so plants will keep them hidden. If you don’t want to use plants, you can use a breeding mop instead.

About a week before you want to start breeding, separate your conjoined pair. Feed the fish live food and keep an eye on the female. She should start fattening up on eggs. When this happens, move the pair to the breeding tank.

Breeding should occur within a day. The female will lay between 50 and 100 eggs over several hours. Once you are done, remove the pair from the breeding tank.

The eggs hatch in about two to three days. For the first week or so, the baby fish will survive from the egg sac. Once they become free swimming, you can provide infusoria as food. About a week later, they will be ready for fried foods of powdered fish or small brine shrimp.

final thoughts

As you can see, these freshwater fish are ideal for just about anyone interested in setting up a home aquarium. The combination of their beauty and low maintenance nature makes them the perfect pet!

If you have any other questions about the care of the Emperor Tetra, we will be happy to help you. Simply contact us via social media (or our website) and we’ll get back to you as soon as possible.

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