Red Eye Tetra – Care, Tank Mates, Feeding & Full Details!

In the mesmerizing world of aquaristics, one species stands out with its captivating presence and vivacious personality – the Red Eye Tetra (Moenkhausia sanctaefilomenae).

Best known for its contrasting vibrant colors and the distinctive red ring around its eyes, this tropical freshwater fish from South America is a favorite among aquarists of all levels of experience.

The Red Eye Tetra’s alluring aesthetic, combined with its hardy nature and peaceful temperament, makes it a staple in community tanks.

Whether you’re a novice aquarist starting your first tank or an experienced hobbyist looking to add a new dynamic to your established aquarium, the Red Eye Tetra can be an excellent choice.

In this comprehensive guide, we’ll dive deep into the world of the Red Eye Tetra, exploring its origins, its natural habitat, and its appearance.

We’ll guide you through the ins and outs of caring for these captivating creatures, providing detailed insights on their diet, tank requirements, breeding, and more.

By the end, you’ll have a rich understanding of the Red Eye Tetra and the knowledge necessary to provide an environment in which they can thrive.

Quick Stats About Red Eye Tetra

Care Level: Easy
Temperament: Peaceful
Color: Shimmery silver with a black tail
Lifespan: ~5 years
Size: ~2.8 inches
Diet: Omnivore
Family: Characidae
Minimum Tank Size: 20 gallons
Tank Setup: Freshwater, live plants, driftwood, rocks
Compatibility: Other tetra species, barbs, and danios

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Red Eye Tetra Appearance

The Red Eye Tetra, as its name implies, is most notably recognized by the vibrant red halo that decorates its eyes.

This striking feature stands out against its silver-hued body, creating a striking contrast that captivates both aquarists and their visitors.

Aside from its iconic eyes, the Red Eye Tetra boasts a somewhat compressed, streamlined body shape ideal for swift movement.

Its body is mostly silvery, adorned with a subtle golden hue that often shines under suitable lighting conditions.

Adding to its visual charm, the Red Eye Tetra’s tail is marked with a broad black band, edged with a thin white line, which lends a stunning finish to its overall appearance.

Natural Habitat of Red Eye Tetra

In the wild, the Red Eye Tetra is found in the warm, tropical freshwater bodies of South America.

It’s accustomed to the soft, slightly acidic waters of the region’s rivers, streams, and floodplains, which are typically dense with vegetation and replete with diverse fauna.

The Red Eye Tetra’s natural habitat profoundly influences its care requirements in an aquarium setting.

Origin and Distribution

The Red Eye Tetra is indigenous to South America, specifically found in the Paraguay Basin, Upper Paraná Basin, and parts of Bolivia and Brazil.

The species thrives in these areas, thanks to the rivers’ perfect blend of water conditions and abundant vegetation, which provides ample hiding and breeding spots.

Despite their South American origins, Red Eye Tetras have made their way around the world through the aquarium trade and are now a common sight in tanks worldwide.

Growth, Size & Lifespan of Red Eye Tetra

Upon reaching full maturity, the Red Eye Tetra typically measures between 2.5 to 3 inches in length, making it a suitable choice for various tank sizes.

The growth rate of these tetras is heavily influenced by factors such as diet, water quality, and overall tank conditions.

As for their lifespan, Red Eye Tetras are known for their longevity. With optimal care and a well-maintained environment, they can live up to 5 years, and in some cases, even longer.

The key to ensuring a long, healthy life for your Red Eye Tetra lies in closely mimicking their natural habitat and adhering to their specific care needs.

Red Eye Tetra

Red Eye Tetra Behavior and Temperament

The Red Eye Tetra is a schooling fish that prefers the company of its kind. These tetras are known for their energetic and social demeanor, and when in a suitable group of at least six, they exhibit the most natural and entertaining behavior.

Despite their active nature, Red Eye Tetras are peaceful and get along well with other community-friendly species, making them an excellent addition to diverse community tanks.

They prefer swimming in the middle to upper levels of the tank, adding a dynamic aspect to your aquarium.

Tank Setup for Red Eye Tetra

Creating a comfortable, inviting space for your Red Eye Tetra involves closely mimicking their natural habitat.

This involves setting up the right tank, selecting a suitable substrate, providing plenty of hiding spots, and ensuring optimal water parameters, among other considerations.

Tank Size

Considering the Red Eye Tetra’s active nature and preference for swimming in schools, a minimum 20-gallon tank is recommended. A larger tank provides ample space for these fish to swim and exhibit natural behavior.


A dark, fine-grained substrate, such as sand or smooth gravel, is preferred for Red Eye Tetra, as it simulates the soft riverbeds found in their native habitats. The dark substrate also helps accentuate the tetras’ vibrant colors.

Decorations and Hiding Spots

Red Eye Tetras thrive in environments that provide plenty of hiding spots. Incorporate various decorations such as driftwood, caves, or rocks.

Aquatic plants, both live and artificial, can also serve as excellent hideaways, closely resembling their natural habitats.

Water Parameters

Strive for water conditions that mirror those of the Red Eye Tetra’s natural habitat. Ideal water parameters include a temperature of 72-79°F, a pH level of 6.0-7.5, and a water hardness of 5-19 dGH.

Filtration and Aeration

A high-quality filter is crucial to maintain water cleanliness and oxygenation. Opt for a filter that can handle the tank’s capacity and ensure it provides gentle water movement to simulate their natural environment.


Moderate lighting is ideal for Red Eye Tetras, as it imitates the sunlight filtered through their natural, densely vegetated habitats. Too much light can cause stress, while too little can hinder their vibrant color display.

Tank Mates

As a peaceful species, Red Eye Tetras can coexist with other similarly sized, non-aggressive fish. Ideal tank mates include Corydoras Catfish, Platies, and Gouramis. However, avoid housing with large or aggressive species that may bully or prey on the Red Eye Tetras.


Red Eye Tetras are omnivores and thrive on a balanced diet of both plant-based and meaty foods. High-quality flake or pellet food can serve as the base diet, supplemented with occasional treats of live or frozen brine shrimp, bloodworms, or daphnia for nutritional variety.

Tank Maintenance of Red Eye Tetra

To keep your Red Eye Tetras in optimal health and display their stunning colors, routine tank maintenance is a must.

The following sections will guide you through essential practices for maintaining a clean, healthy aquarium environment.

Regular Water Changes

Water changes are a fundamental aspect of tank maintenance. We recommend a weekly water change of 25-30% for Red Eye Tetras.

This helps maintain the water parameters within the desired range, removing any excess nutrients and waste that could potentially harm your fish or cloud the water.

Cleaning the Tank and Decorations

Cleaning the tank and decorations should be part of your regular maintenance routine. This helps prevent the accumulation of algae and harmful bacteria.

Gently scrub the tank’s sides and rinse the decorations with warm water. Avoid using any chemical-based cleaning agents as they can be harmful to your fish.

Filter Maintenance

Your aquarium filter plays a significant role in maintaining a healthy environment for your Red Eye Tetras. Regularly check and clean the filter, but be careful not to overclean it as beneficial bacteria live within the filter media.

Replace the filter media as per the manufacturer’s instructions.

Monitor Fish Health

Keeping a close eye on your Red Eye Tetras’ health is essential. Look for any changes in their behavior, eating habits, or appearance.

Common signs of stress or illness include lethargy, loss of appetite, faded colors, or unusual spots. Early detection can often make the difference between recovery and severe illness.

Red Eye Tetra

Red Eye Tetra Acclimation

Bringing a Red Eye Tetra home from the pet store is a joyful occasion. However, introducing these delicate creatures to their new environment requires careful acclimation.

This step is crucial as sudden changes in water conditions can stress fish and potentially lead to health complications.

Start by leaving the bag containing your new Red Eye Tetras floating in the aquarium for about 15-20 minutes. This allows the water inside the bag to gradually adjust to the aquarium’s temperature.

Next, slowly add small amounts of aquarium water to the bag every 10 minutes. Repeat this step over the course of an hour. Once done, gently use a net to transfer the fish into the aquarium.

Avoid pouring the bag water into your tank to prevent the introduction of any potential contaminants.

Red Eye Tetra Diet and Feeding

Red Eye Tetras are omnivorous by nature, relishing both plant-based food and small live or frozen invertebrates.

Offering a diverse, balanced diet will not only keep your Tetras healthy but also enhance their vibrant colors.

Here’s a detailed breakdown of what you can incorporate into their diet:

High-Quality Flake Food

A good quality tropical fish flake food forms an excellent base for the Red Eye Tetra diet. These flakes are usually nutritionally balanced, easy to consume, and readily available at pet stores.

Live or Frozen Foods

To supplement their diet, provide live or frozen foods such as brine shrimp, daphnia, or bloodworms. These provide valuable protein and help replicate their natural feeding habits.


Vegetables like zucchini or cucumber slices, blanched spinach, or peas (shelled and crushed) are great additions. These provide necessary vitamins and minerals.

Feeding Schedule

Feed your Red Eye Tetras twice a day, providing only as much food as they can consume within a few minutes. Overfeeding can lead to poor water quality and health issues. Any uneaten food should be removed promptly to avoid water contamination.

Remember, a varied diet is the key to a healthier, happier, and longer-lived Red Eye Tetra.

Ideal and Incompatible Tank Mates for Red Eye Tetras

When planning an aquatic community, selecting the right tank mates for your Red Eye Tetras is crucial.

Their peace-loving nature and group-oriented behavior make them suitable for a variety of compatible species, yet some fish should be avoided.

Compatible Tank Mates

Red Eye Tetras are sociable fish that enjoy the company of their own kind, as well as that of other peaceful species.

Ideal tank mates include:

  1. Rummy Nose Tetras – They share similar water parameter requirements and their peaceful temperament matches well with Red Eye Tetras.

  2. Mollies – These are gentle-natured fish that won’t hassle the Red Eyes.

  3. Harlequin Rasboras – Their calm nature makes them compatible with most community tanks.

  4. Corydoras Catfish – These bottom dwellers will not compete with Red Eye Tetras for space.

  5. Dwarf Gourami – Their peaceful disposition makes them a good fit.

  6. Cardinal Tetras – They thrive in similar conditions and make good companions.

  7. Platies – Their non-aggressive behavior works well with Red Eye Tetras.

Tank Mates to Avoid

Avoid keeping Red Eye Tetras with large, aggressive fish that could intimidate or harm them.

These include:

  1. Oscars – Known for their aggression, they could potentially harm smaller fish.

  2. Bettas – Their territorial behavior doesn’t mesh well with the peaceful Red Eye Tetras.

  3. Cichlids (like Jack Dempsey or Jewel Cichlids) – Many of them are aggressive and larger, posing a threat to Red Eye Tetras.

  4. Red Tail Sharks – Their territorial nature can lead to conflicts.

  5. Arowanas – Due to their large size, they may view Red Eye Tetras as food.

Breeding Red Eye Tetras and Fry Care

Breeding Red Eye Tetras is a rewarding experience but requires a separate breeding tank and optimal conditions.

Here’s a step-by-step guide:

Preparing the Breeding Tank

Set up a separate 10-20 gallon breeding tank with soft and slightly acidic water. Include fine-leaved plants or a spawning mop for the female to deposit her eggs.

Conditioning the Breeders

Feed potential breeders a high-quality diet of live or frozen foods for a week or two before breeding to encourage egg production.


Place the conditioned pair in the breeding tank. The female will scatter her eggs among the plants, which the male will then fertilize.

Post-Spawning Care

Immediately after spawning, remove the adult fish from the tank to prevent them from eating the eggs.

Fry Care

The eggs should hatch within 24-36 hours. Once the fry are free-swimming, feed them infusoria or commercially available fry food. After a week or two, you can gradually introduce micro worms or freshly hatched brine shrimp.

Maintaining optimal water conditions is crucial during this stage, as fry are particularly sensitive to water quality. Regular, small water changes and careful monitoring will give your Red Eye Tetra fry the best start in life.

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Identifying Stress in Red Eye Tetras

Stress can significantly impact the health of your Red Eye Tetras.

It’s crucial to monitor their behavior regularly and understand the signs that your fish may be stressed:

  1. Lethargy: If your Tetras are not as active as they usually are, they may be under stress.

  2. Loss of Appetite: Red Eye Tetras are generally hearty eaters. A sudden decrease in appetite may indicate stress.

  3. Color Fading: Stress can cause these vibrant fish to lose their color.

  4. Gasping at the Surface: This could suggest that your fish are stressed due to poor water quality or lack of oxygen.

  5. Disease Symptoms: Stress can lower fish’s immune systems, making them more susceptible to diseases. Look out for visible signs like spots, bloat, or fin rot.

Common Health Issues and Treatments for Red Eye Tetras

Red Eye Tetras, like any other fish, can suffer from a range of common aquatic diseases:

  1. Ichthyophthirius (Ich): Also known as White Spot Disease, Ich is a parasitic condition recognizable by white spots on the fish’s body and gills. Treat it with a specialized Ich treatment available at pet stores.

  2. Fin Rot: This bacterial infection causes the fins to look ragged and frayed. Early stages can be treated with antibacterial medication and good water quality.

  3. Fungal Infections: These are often caused by poor water quality or untreated injuries. Antifungal medication is effective in most cases.

Always quarantine new fish before introducing them to the main tank, and maintain good water quality to prevent diseases.

Additional Tips for a Healthy Aquarium

To ensure your Red Eye Tetras live a healthy life, here are some tips:

  1. Routine Maintenance: Regular water changes and tank cleaning are essential.

  2. Monitor Water Parameters: Keep track of the water temperature, pH, hardness, and nitrate levels.

  3. Balanced Diet: Feed your Tetras a balanced diet of high-quality flakes, pellets, and occasional live or frozen foods.

  4. Avoid Overcrowding: Keep the population of your tank in check to prevent stress and aggression.

  5. Provide Plenty of Hiding Spots: Plants, rocks, and decorations can help fish feel more secure.

Should You Get a Red Eye Tetra for Your Aquarium?

If you’re seeking a vibrant, lively addition to a community tank, the Red Eye Tetra may be the ideal choice. They’re relatively easy to care for, making them suitable for both beginner and experienced aquarists.

Their sociable nature, coupled with their vibrant color and active behavior, adds life to any aquarium. However, they do require a certain level of care, including regular tank maintenance and a balanced diet.

If you’re ready to meet these needs, the Red Eye Tetra could make a fantastic addition to your aquatic family.

Red Eye Tetra Conservation Status

Red Eye Tetras (Moenkhausia sanctaefilomenae) are not listed as endangered or vulnerable species by the International Union for Conservation of Nature (IUCN).

They are commonly found in South American rivers and their population seems stable.

However, they are still subject to threats such as habitat loss and pollution, reinforcing the importance of responsible pet ownership and industry practices.

Availability & Pricing of Red Eye Tetras

Red Eye Tetras are readily available in most pet stores due to their popularity among aquarists. These fish are often mass-bred in captivity, making them a sustainable choice for fishkeepers.

The pricing for Red Eye Tetras is generally affordable, which makes them an excellent option for beginner fish enthusiasts.

The average cost may vary based on the size and health of the fish, but you can generally expect to pay a few dollars per fish.

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Frequently Asked Questions About Red Eye Tetras

1. How Long Do Red Eye Tetras Live?

Red Eye Tetras can live up to 5 years in well-maintained aquariums with optimal water conditions and a balanced diet.

2. Can Red Eye Tetras Live With Other Fish?

Yes, they are peaceful and make great community fish. They get along well with similarly sized, non-aggressive species.

3. How Many Red Eye Tetras Should Be Kept Together?

They are schooling fish and should be kept in groups of at least 5-6. A larger school will help them feel safer and exhibit more natural behavior.

4. What Do Red Eye Tetras Eat?

They are omnivorous and will eat a range of foods, including flakes, pellets, and live or frozen foods like brine shrimp or daphnia.


In summary, the Red Eye Tetra is a vibrant, easy-to-care-for freshwater fish that makes a striking addition to any community aquarium.

Their bright coloring, peaceful temperament, and active nature make them a joy to observe. With proper care, optimal water conditions, and a nutritious diet, Red Eye Tetras will thrive, providing an engaging display of natural behavior and interactions.

Whether you are a beginner or a seasoned aquarist, the Red Eye Tetra could be the perfect addition to your aquatic family.