Penguin Tetra

The Fascinating Penguin Tetra: Thayeria boehlkei (2023-24)

Dive into the world of Penguin Tetra (Thayeria boehlkei) - a fascinating and peaceful aquarium fish. Learn about its unique traits and care.


In the realm of aquarium fish, few species captivate enthusiasts quite like the Penguin Tetra, scientifically known as Thayeria boehlkei. This peaceful and adaptable schooling fish hails from the lush waters of Peru and Brazil, where it thrives amidst serene companions. In this comprehensive guide, we delve into the intriguing world of the Penguin Tetra, exploring its natural habitat, tank requirements, preferred diet, and compatible tank mates. With our expert insights, you’ll discover how to create an ideal environment for these captivating fish and enjoy their captivating presence in your aquarium.

Penguin Tetra Overview

Scientific nameThayeria boehlkei
Common namePenguin Tetra
OriginNative to Peru and Brazil
SizeUp to 3 inches
Life expectancyApproximately 5-8 years
Different ColorsSilver bodies with a black stripe
DietPrepared fish food, freeze-dried, frozen, or live foods
TemperamentPeaceful and social
Tank sizeMinimum of 20 gallons
Temperature72°F to 82°F (22-28°C)
pH6.0 to 8.0
Water Hardness level (TDS)Tolerates a wide range of water conditions
Care levelEasy
Breeding styleRequires a separate spawning tank
Compatible fishVarious calm species, compatible tank mates
Type of Tank most suitableDensely planted tank with live protein and dim lighting
Tank MatesPeaceful inhabitants of community tanks

Origin and Natural Habitat

The Penguin Tetra finds its origin in the pristine waters of Peru and Brazil. Here, the dense greenery and dim lighting of their natural habitat create a serene environment for these remarkable creatures. Living in schools, the Penguin Tetra embraces safety in numbers, which helps to reduce any fin-nipping tendencies. Their fascinating partially upright swimming style and striking signature black stripe make them stand out among other fish species.

Physical Characteristics

Distinguishing male from female Penguin Tetras is an enjoyable pursuit, with males displaying more vibrant and intense colors. These unique physical traits play a vital role in their natural environment, helping them thrive and stand out among their peers. Understanding these characteristics enhances our appreciation of their beauty and significance.

Tank Setup and Requirements

To accommodate the peaceful and active nature of the Penguin Tetra, creating the right environment is crucial. A well-planted tank with ample swimming space will keep these fish content and healthy. The presence of dense greenery emulates their natural habitat and provides shelter, reducing stress levels.

In terms of water conditions, the Penguin Tetra proves to be remarkably adaptable. They can thrive in a wide range of pH levels, ideally ranging from 6.0 to 8. A moderate hardness level of 5 to 20 dKH is suitable for their well-being. Maintaining the water temperature between 72°F to 82°F (22-28°C) ensures optimal comfort.

For optimal happiness and well-being, consider providing a larger tank for these sociable creatures. While a 20-gallon tank can work, a more spacious 30-gallon tank is highly recommended for accommodating larger groups.

Diet and Feeding

The Penguin Tetra follows an omnivorous diet, displaying a hearty appetite for both prepared and live foods. To keep them in the best of health, offer a varied diet that includes high-quality flakes, pellets, and occasional live treats. Their adaptability extends to their eating habits, making them relatively easy to feed and care for.

Compatible Tank Mates

One of the joys of owning a peaceful community tank is selecting compatible tank mates for the Penguin Tetra. These amiable fish thrive in the presence of fellow tetra species, such as Neon Tetras, Cardinal Tetras, or Rummy Nose Tetras. Rasboras and loaches also make for excellent companions. The key is to choose calm and non-aggressive species to ensure harmonious coexistence.

Breeding Considerations

Breeding Penguin Tetras requires some thoughtful preparation. To encourage successful breeding, consider setting up a separate spawning tank with fine-leaved plants for egg protection. Proper conditioning and a well-monitored environment will aid in fostering a successful breeding process. While not the easiest species to breed, the rewarding experience of witnessing new life will make the efforts worthwhile.

Here’s a more detailed guide on breeding Penguin Tetras:

1. Condition the Breeding Pair: Before initiating the breeding process, it’s essential to condition the breeding pair. Ensure that the male and female Penguin Tetras are in optimal health and have been well-fed with a varied diet. Providing high-quality live and frozen foods will enhance their readiness for breeding.

2. Setting up the Breeding Tank: Prepare a separate breeding tank to isolate the breeding pair from other tank inhabitants. The tank should have similar water conditions to the main tank but with softer and slightly acidic water. Use fine-leaved plants or spawning mops as breeding sites to encourage egg-laying.

3. Introduction and Courtship: Introduce the conditioned male and female Penguin Tetras into the breeding tank. Observe their behavior closely as they begin to court each other. The male may display intense colors and perform courtship rituals to attract the female.

4. Spawning Behavior: During the breeding process, the female will scatter adhesive eggs among the plants or spawning mops. The male will then fertilize the eggs. It’s crucial to watch for this spawning behavior and ensure that the eggs are not eaten by the breeding pair or other tank inhabitants.

5. Remove the Parents: After spawning is complete, promptly remove the breeding pair from the breeding tank to prevent them from consuming the eggs. The parents may not provide parental care, and leaving them in the breeding tank can lead to the eggs being eaten.

6. Incubation Period: The fertilized eggs will hatch in about 24 to 48 hours. During this time, it’s essential to maintain stable water conditions and keep the breeding tank well-maintained.

7. Fry Care: Once the fry hatch, they will initially survive on their yolk sacs. After a few days, they will become free-swimming. Offer them infusoria, liquid fry food, or newly hatched brine shrimp as their first foods. Ensure proper filtration and maintain excellent water quality to support their growth.

8. Gradual Transfer to Main Tank: As the fry grows and become more robust, consider transferring them to the main community tank. Ensure that the tank mates in the main tank are compatible and will not harm the fry.

Breeding Penguin Tetras can be a challenging but rewarding endeavour. Patience, careful observation, and providing the right conditions are essential for a successful breeding experience. The sight of tiny fry growing into adult Tetras is a fascinating process that can bring joy to any fish keeper.

Disease Prevention and Treatment

Disease prevention and treatment are crucial aspects of maintaining the health and well-being of Penguin Tetras (Thayeria boehlkei) in an aquarium. These peaceful and social fish can be susceptible to various diseases, but with proper care and preventive measures, you can minimize the risk and provide a safe environment for your Tetras. Here’s an in-depth guide on disease prevention and treatment for Penguin Tetras:

1. Quarantine New Fish: Whenever introducing new fish or plants to the aquarium, it’s essential to quarantine them separately before adding them to the main tank. Quarantine helps prevent the introduction of potential diseases or parasites into the established aquarium. Monitor the quarantined fish closely for signs of illness before allowing them to join the main community tank.

2. Maintain Excellent Water Quality: Consistently monitor and maintain excellent water quality in the aquarium. Regularly test the water parameters, including ammonia, nitrite, nitrate levels, pH, and temperature. Penguin Tetras prefer stable water conditions, and maintaining pristine water quality helps reduce stress and prevent diseases.

3. Provide Proper Nutrition: Offer a well-balanced and nutritious diet to boost the immune system of the Penguin Tetras. Provide a mix of high-quality dry foods, frozen foods, and live foods to ensure they receive essential nutrients. A varied diet helps strengthen their resistance to diseases.

4. Observe Behavioral Changes: Monitor the behavior of the Penguin Tetras daily. Unusual swimming patterns, loss of appetite, lethargy, or hiding can be signs of underlying health issues. Early detection of behavioral changes can lead to prompt action and early treatment if necessary.

5. Isolate Sick Fish: If you notice any signs of illness or disease in a Penguin Tetra, immediately isolate the affected fish in a separate quarantine tank. This prevents the spread of the disease to other tank mates and allows for focused treatment.

6. Diagnose and Treat Diseases Promptly: If a disease outbreak occurs, accurately diagnose the specific ailment before starting treatment. Consult a qualified veterinarian or seek advice from experienced aquarium hobbyists if needed. Avoid using medications blindly, as incorrect treatments can worsen the condition or harm other tank inhabitants.

7. Common Diseases and Treatments: Some common diseases that may affect Penguin Tetras include ich (white spot disease), fin rot, and bacterial infections. Ich can be treated with aquarium salt, increased temperature, and medication containing formalin or malachite green. Fin rot and bacterial infections may require antibiotic treatment.

8. Minimize Stress: Stress weakens the immune system of fish, making them more susceptible to diseases. Minimize stress by providing adequate hiding spots, maintaining a stable environment, and avoiding sudden changes in water parameters.

9. Regular Tank Maintenance: Perform regular water changes and clean the aquarium to remove debris and uneaten food, which can contribute to poor water quality and potential disease outbreaks.


The Penguin Tetra, or Thayeria boehlkei, is a true gem among aquarium fish. With their peaceful demeanour, unique appearance, and adaptability, they bring joy and tranquillity to any community tank. By providing the ideal tank setup, a varied and nutritious diet, and compatible tank mates, you can ensure the well-being and happiness of these captivating fish. Whether you are a seasoned aquarium enthusiast or a beginner, the Penguin Tetra will undoubtedly leave a lasting impression on your heart and mind.


What is the distinctive swimming style of the Penguin Tetra?

The Penguin Tetra exhibits a distinctive swimming style with their bodies slightly tilted upward, setting them apart from other fish.

How do the bodies of Penguin Tetras appear when swimming?

The bodies of Penguin Tetras appear slightly tilted upward as they swim, which is characteristic of their unique swimming style.

What makes the appearance of Penguin Tetras fascinating to watch?

The silver bodies with a black stripes and translucent fins of the Penguin Tetras make them fascinating to watch, attracting aquarium enthusiasts.

Where are Penguin Tetras native to?

Penguin Tetras are native to the Amazon River Basin in South America, primarily in Peru and Brazil.

In which countries can you find Penguin Tetras in the wild?

You can find Penguin Tetras in the wild in the Amazon River Basin, which spans across South American countries like Peru and Brazil.

Are Penguin Tetras peaceful or aggressive in nature?

Penguin Tetras are peaceful in nature, making them suitable for community aquariums.

Do Penguin Tetras form schools in the wild?

Yes, in the wild, Penguin Tetras form schools, exhibiting their social behavior.

What types of tank mates can coexist well with Penguin Tetras?

Penguin Tetras coexist well with various compatible tank mates, including Neon Tetras, Cardinal Tetras, and Rummynose Tetras.

Can Penguin Tetras live with non-fish aquatic creatures?

Yes, Penguin Tetras can share their tank with non-fish aquatic creatures like freshwater shrimp and snails.

What are the key elements for maintaining a well-maintained aquarium?

Maintaining a well-maintained aquarium for Penguin Tetras involves proper tank setup, suitable water parameters, and a balanced diet.

How should the tank setup be for Penguin Tetras?

The tank setup for Penguin Tetras should include appropriate decorations and hiding spots, emulating their natural habitat.

What are the suitable water parameters for Penguin Tetras?

Penguin Tetras prefer stable water parameters, including the right pH levels, hardness, and temperature range.

What type of diet is essential for the well-being of Penguin Tetras?

A balanced diet, including both commercial and live foods, is essential for the well-being of Penguin Tetras.

How large can Penguin Tetras grow, and what is their lifespan?

Penguin Tetras can grow up to 3 inches in length and have a lifespan of approximately 5-8 years.

What is the process of breeding Penguin Tetras?

Breeding Penguin Tetras requires a separate breeding tank, a suitable breeding site, and monitoring for spawning behavior.

What do you need for setting up a separate breeding tank?

For setting up a separate breeding tank, you need to provide suitable plants or moss for egg protection.

Which behaviors should be monitored during breeding?

During breeding, monitor the courtship rituals and egg-laying habits of the Penguin Tetras.

What are some related species to consider alongside Penguin Tetras?

Some related species to consider alongside Penguin Tetras include Neon Tetras, Cardinal Tetras, and Rummynose Tetras.

How many Penguin Tetras can be kept together in a group?

Penguin Tetras should be kept in groups of six or more to ensure their well-being and social behavior.

Why is a secure lid necessary for tanks with Penguin Tetras?

Penguin Tetras are capable of jumping out of the tank, so a secure lid is necessary to prevent any escapes and ensure their safety.


Organization NameInternet Link
Food and Agriculture Organization (FAO)FAO Penguin Tetra Care Guide
World Wildlife Fund (WWF)WWF Penguin Tetra Conservation
International Union for Conservation of Nature (IUCN)IUCN Red List – Penguin Tetra
Global Biodiversity Information Facility (GBIF)GBIF Penguin Tetra Data
World Association of Zoos and Aquariums (WAZA)WAZA Aquarium Care Guidelines

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