Red Eye Tetra: Species Profile and Complete Care Guide

Scientifically known as Moenkhausia_sanctaefilomenae
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: July 16, 2024
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Ever wonder why your Red Eye Tetras just don’t seem to flourish? Clear up the mystery with our full care guide. Learn about their needs, perfect tank mates, and handy tips for a vibrant and happy aquarium. Keep reading for success in caring for Red Eye Tetras!

Article Summary

  • Red Eye Tetras are visually stunning fish with silver bodies and striking red eyes.
  • They thrive in groups of at least six individuals, promoting natural behavior and reducing stress.
  • Red Eye Tetras have an omnivorous diet and should be fed a balanced variety of foods.

Species Summary: A Tropical Freshwater Fish

The red eye tetra, scientifically known as Moenkhausia sanctaefilomenae, is a fascinating member of the Characidae family. Native to Brazil, Paraguay, Bolivia, and other parts of South America, this species can be found in various habitats such as rivers, streams, and flooded areas throughout its distribution range.

Red Eye Tetra Appearance

The Red Eye Tetra is a visually stunning fish with its silver body and striking red eyes. Its silver coloration adds a touch of elegance to any aquarium, making it a popular choice among fish enthusiasts. The bright red eyes of this species are particularly eye-catching, creating a captivating contrast against its silver scales.

Their medium size allows them to comfortably swim and navigate through the aquarium…

In terms of size, the Red Eye Tetra is considered a medium-sized fish species. On average, they can grow to be around 2 to 2.5 inches long, making them suitable for various tank sizes. Their medium size allows them to comfortably swim and navigate through the aquarium while still being small enough to fit in community tanks with other compatible fish species.

The Red Eye Tetra exhibits distinct differences between males and females. Females tend to have a more heterochromatic nature, meaning they display a wider range of colors than males. This can include variations in the intensity of their silver coloration and the brightness of their red eyes. In contrast, males generally have a more uniform appearance, consistent silver color, and red eyes.

Red Eye Tetra Species Highlights

Red Eye Tetra Behavior

Red eye tetras are known for their energetic swimming behavior, darting in and out of hiding places. They are constantly on the move, creating a lively and dynamic atmosphere in the aquarium.

These fish are peaceful but can display aggression towards slower-moving fish. It is important to provide them with enough space and suitable tank mates to prevent conflicts.

A larger group of Red Eye Tetras enhances their natural behavior…

Red eye tetras are shoaling fish and thrive in groups of at least six individuals. Being in a group helps them feel more secure and reduces stress. Additionally, a larger group enhances their natural behavior and promotes better health and well-being.

Tank Requirements

Red Eye Tetras in a Tank With Live Plants
Red Eye Tetras in a Tank With Live Plants

Red eye tetra is highly adaptable and thrives in standard tropical tank setups. However, to ensure their well-being and create an environment that mimics their natural habitat, there are a few key considerations to remember.

Water Conditions

Maintain a pH range of 6.8 – 7.8, water hardness between 50 – 140 ppm, and a temperature range of 75° – 80°F. These parameters will provide the optimal conditions for red eye tetras to flourish.

Tank Size

Red eye tetras require a tank size of 20 – 30 gallons to accommodate their active nature and schooling behavior. Providing ample swimming space is essential for their overall health.

Aquarium Setup

Incorporate live plants, driftwood, and rocks to replicate their natural environment. This will enhance the aesthetic appeal and provide hiding spots and shaded areas where red eye tetras can feel secure.

Water Filtration and Heating

Install a reliable filtering system to maintain water quality by removing toxins and debris. An aquarium heater should regulate the temperature consistently within the recommended range.

Red Eye Tetra Tank Mates

When selecting tank mates for red eye tetras, opt for peaceful species with similar water conditions. Suitable companions include other tetra species, rainbowfish, barbs, and danios.

Other Tetra Species

Red eye tetra and other tetra species suit a tank environment. Tetras, like the bleeding heart tetra, are known for their peaceful nature, making them great companions for other fish in a community tank. Tetras are generally hardy and easy to care for, making them suitable for beginner and experienced fish keepers.


Both the red eye tetra and rainbowfish are suitable for a tank environment. The red eye tetra is a peaceful and active fish that can thrive in a community tank. They prefer to swim in schools, so keeping them in groups of at least six individuals is recommended.

Rainbowfish are also peaceful and colorful fish that can coexist with various tank mates. Rainbowfish are generally larger than red eye tetras, with some species reaching lengths up to 6 inches. They are active swimmers and require plenty of open swimming space in the tank.

The red eye tetra and rainbowfish can be a great addition to a well-maintained tank, but it is important to ensure that the tank size and water parameters suit their specific needs.


Both the red eye tetra and barbs are suitable for a tank environment. The red eye tetra is a peaceful and active fish that can thrive in a community tank, making it an excellent choice for aquarium enthusiasts. They prefer to swim in schools, so keeping them in groups of at least six individuals is recommended.

Similarly, barbs are peaceful fish that can coexist with various tank mates. Barbs are generally larger than red-eye tetras, with some species reaching lengths up to 4 inches. They are active swimmers and require plenty of open swimming space in the tank.


The barbs and red-eye tetra both have the potential to enhance a well-maintained tank. Ensure the tank size and water conditions cater to their distinct requirements.


The red eye tetra and danios are popular for aquarium enthusiasts due to their suitability for tank life. Both species are known for their peaceful behavior, making them compatible with various tank mates. Additionally, they are relatively hardy and can adapt well to different water conditions.

Danios are known for their energetic swimming patterns, which can create a lively and dynamic tank environment.

Both species are also relatively small, making them suitable for smaller tanks. Overall, the red eye tetra and danios are great for aquarium hobbyists looking to add beauty and activity to their tanks.

Species to Avoid For Red Eye Tetra

Avoid aggressive fish like bettas, cichlids, oscars, or flowerhorns, as they may cause stress or harm.


Bettas are fish that should be avoided when considering tank mates for red eye tetras. While bettas are famous and beautiful, they are known for their aggressive behavior, especially towards other fish with long, flowing fins like the red eye tetra.

Betta fish are territorial and may see the red eye tetra as a resource threat or competition. This can lead to stress, injury, or even death for the red eye tetra. It is best to keep bettas in a tank alone or with other non-aggressive fish species that can tolerate their behavior.


Cichlids are not recommended to be kept in the same tank as red eye tetras. Cichlids are known to be aggressive and territorial fish, and they may pose a threat to the peaceful and delicate nature of red eye tetras. Cichlids are known to chase and nip at other fish, which can cause stress and potential harm to the tetras.

Additionally, cichlids require larger tanks with specific water conditions, which may not be suitable for the red eye tetra. It is best to avoid keeping cichlids and red eye tetra together to ensure the well-being and safety of both fish species.


Flowerhorn cichlids should be avoided in a tank with red eye tetras. Flowerhorns are known for their aggressive behavior and territorial nature. They can grow quite large and require a spacious tank to thrive.

On the other hand, red eye tetras are peaceful schooling fish that prefer to be in a group. The aggressive nature of flowerhorns can cause stress and harm to the red eye tetras, leading to potential injuries or even death. It is best to keep flowerhorns in a separate tank or choose tankmates more compatible with their aggressive behavior.


Oscars should not be kept in the same tank as red eye tetras. Oscars are large and aggressive fish that can grow up to 12 inches in size, while red eye tetras are smaller and more peaceful. The size difference alone can lead to the Oscars viewing the tetras as potential prey, causing stress and potential harm to the tetras.

Additionally, Oscars are known to be territorial and may become aggressive toward other fish in the tank, especially if they feel their territory is being invaded. This aggression can lead to injuries or even death for the red eye tetras. Therefore, it is best to avoid keeping Oscars and red eye tetras together in the same tank to ensure the well-being and safety of both fish species.

By ensuring proper tank requirements such as suitable tank size, appropriate water conditions, adequate filtration system with heating capabilities, and compatible tank mates, you can create an ideal home aquarium for your vibrant red eye tetras.

Red Eye Tetra Health

Red eye tetra is small, vibrant fish popular among aquarium enthusiasts. In this section, we will explore various aspects of their diet and feeding habits and discuss possible diseases they may be susceptible to.

We will also delve into preventive measures that can be taken to ensure their well-being, as well as potential treatments for any ailments they may develop. Lastly, we will touch upon the average lifespan of red eye tetras and provide insights into how to maximize their longevity.

Diet and Feeding

Red Eye Tetras have an omnivorous diet, meaning they consume a variety of food sources in their natural habitat. When kept in aquariums, providing them with a balanced diet is essential to ensure their nutritional needs are met.

Commercial fish food can serve as the main component of their diet, but it should be supplemented with other options such as daphnia, brine shrimp, and bloodworms. These supplementary foods offer additional nutrients and variety to their diet.

Overfeeding can lead to health issues and water quality problems…

Feeding frequency is an important consideration when it comes to Red Eye Tetras. It is recommended to feed them regularly but in moderate amounts. Overfeeding can lead to health issues and water quality problems in the aquarium.

By feeding them in moderation, you can prevent overeating and maintain a healthy balance in their diet. A consistent feeding schedule will also help establish a routine for the fish and ensure they receive the necessary nutrients without overindulging.

Possible Diseases

Red Eye Tetras are generally resilient but susceptible to common freshwater diseases, such as ich, a parasitic infection. Early detection and prompt treatment are crucial in combating this concern. Proper care and maintenance are essential to ensure good health and prevent disease.

Neon Tetra Disease (NTD)

Neon Tetra Disease (NTD) is caused by a parasite called Pleistophora hyphessobryconis. It is a highly contagious disease that can lead to a decline in the overall health and vitality of the infected fish.

NTD is another disease that affects tetras, including Red Eye Tetras. If NTD is suspected, it is best to quarantine the affected fish and consult a veterinarian for guidance.

Average Lifespan

The average lifespan of Red Eye Tetra in aquariums is around five years. This may differ from their lifespan in the wild due to various factors.

Breeding Red Eye Tetra

A School of Red Eye Tetras
A School of Red Eye Tetras

Breeding Red Eye Tetras in captivity is exciting for aquarium fish enthusiasts. These beautiful fish, also known as redeye tetras, are popular among tropical fishkeepers due to their vibrant red eyes and stunning appearance.

Pairing Behavior of Red Eye Tetra

One fascinating aspect of breeding red eye tetras is observing their natural pairing and egg-laying behavior. These schooling fish form breeding pairs during the spawning season in the wild. The female red eye tetra lays adhesive eggs on plants or other surfaces while the male fertilizes them. This behavior can be replicated in a breeding tank by providing suitable conditions such as soft but slightly acidic water and ample hiding places.

Separate Tank With Floating Plants

Floating plants serve a crucial purpose in breeding tanks for these freshwater fish. These plants provide a natural and comfortable environment for the fish and play a significant role in the breeding process.

These plants create a sense of security for the tetras, miming their natural habitat and making them feel more at ease. This is particularly important during breeding, as stressed or uncomfortable fish may not exhibit the desired behaviors for successful reproduction.

To increase the chances of successful breeding, keeping a group of at least six red eye tetras consisting of three males and three females is recommended. This helps create a conducive environment for pair formation and minimizes aggression between individuals. Separating the breeding pair into a separate tank with appropriate water parameters further enhances their chances of spawning.

Varied Diet: Flake Food, Brine Shrimp, etc.

Diet is crucial in ensuring optimal health and reproductive success for red eye tetras. A varied diet consisting of high-quality flake food, live or frozen brine shrimp, daphnia, or bloodworms should be provided to condition the fish for breeding. Offering small frequent meals throughout the day can stimulate their instincts.

Care For Fry

Once the eggs are laid, it’s essential to protect them from being eaten by adult fish or other tank inhabitants. A breeder box or net can help safeguard the eggs until they hatch into fry. Maintaining pristine water conditions and providing suitable food options for the newly hatched fry will greatly increase their chances of survival.

Breeding these freshwater fish allows aquarists to witness nature’s wonders within their tanks. By understanding their natural behaviors, providing optimal conditions, and diligently protecting the eggs and fry, hobbyists can enjoy the rewarding experience of successfully raising these captivating fish.

Red Eye Tetra Availability and Price

Red eye tetras are readily available in most pet stores specializing in tropical fish species. They can be found easily, making them popular among beginner aquarists. These vibrant little fish are known for their striking red eyes, which add a unique touch to any aquarium.

Red eye tetra is an excellent option. They are generally inexpensive, allowing aquarists on a budget to enjoy their beauty without breaking the bank. Prices may vary depending on the size and quality of the fish, but they remain relatively affordable overall.

However, it is essential to consider the conditions under which these tetras are kept before purchasing them. It is advisable to buy from reputable sources that prioritize the health and well-being of their fish. This ensures that you receive high-quality specimens free from diseases or other issues.

Before bringing home your red eye tetras, take a moment to inspect their condition. Look for bright colors, active swimming behavior, and clear eyes as signs of good health.


Avoid purchasing any fish that appear lethargic or show signs of illness.

Frequently Asked Questions

How to Take Care of a Redeye Tetra?

Taking care of a Redeye Tetra involves maintaining a well-balanced aquarium environment. Ensure the water temperature is around 72-79°F (22-26°C) and maintain a pH of 6.0 to 7.5. Provide ample hiding spots with plants and caves and good water filtration. Feed them a varied diet, including high-quality flakes, pellets, and occasional live/frozen foods.

How Many Red Eye Tetras Should Be Kept Together?

Redeye Tetras are social fish that thrive in groups. Keeping them in schools of at least 6 individuals is recommended, but a larger group of 10 or more is even better. This helps reduce stress and promotes their natural behavior.

What Fish Can I Keep with Red Eye Tetras?

Redeye Tetras are generally peaceful and can coexist with other small, peaceful fish like other tetra species, gouramis, rasboras, and some types of Corydoras catfish. Avoid aggressive or fin-nipping fish to ensure a harmonious tank environment.

How Long Do Redeye Tetras Live For?

On average, Redeye Tetras have a lifespan of about 3 to 5 years. Some individuals might live longer with proper care and a suitable environment.

What Is the Behavior of a Red Eye Tetra?

Redeye Tetras are active and social fish. They tend to swim together in schools, displaying shoaling behavior. They are mid-level swimmers and appreciate having plenty of plants and hiding spots. Occasionally, they might display minor territorial behaviors, but overall, they are peaceful and make great additions to community aquariums.

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