Information, Characiformes (Characins), Freshwater fish, Species, Tetras

Penguin tetra: Complete Species & Care Overview

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by Jason Matthews



The Penguin Tetra, also known as the False Penguin Tetra, is a unique and captivating fish species that are sure to please any pet fish enthusiast. The Penguin Tetra, with its distinctive black and white markings and playful behavior, is a favorite among novice and experienced fish owners. 

This article will delve into the origin, appearance, size, gender, behavior, and other important aspects of this fascinating fish species. We will provide you with all the information you need to properly care for your Penguin Tetra and ensure their health and happiness, from understanding the ideal tank conditions and compatible tankmates to learning about their diet and breeding habits. 

So, whether you’re a first-time fish owner or an experienced aquarist, keep reading to learn everything there is to know about the Penguin Tetra.


Scientific Name: Thayeria obliqua
Common Names: Penguin Tetra, Blackline penguinfish, False Penguin Tetra
Life Expectancy: 3-5 years
Adult Size: up to 2.5 inches


HabitatAmazon Basin
OriginSouth America
Care LevelEasy
TemperamentPeaceful, schooled fish
DietOmnivorous; eats flake food, frozen food, and live food
Tank LevelMiddle to bottom
Minimum Tank Size20 gallons
Water pH6.0-7.0
Water Temperature72-79°F
Water Hardness4-20 dGH
Tank MatesPeaceful community fish, such as tetras, rasboras, and catfish

Fun Fact Corner

Penguin Tetras are known for their playful and active behavior in the tank, which is a fun fact about them. They are frequently seen swimming in small groups and chasing each other around, creating an exciting and dynamic display in your tank. 

Furthermore, these fish are known for their distinctive “penguin-like” swimming style, in which they swim at an angle, giving the appearance of a penguin waddling. This behavior is unique to the species and contributes to their popularity among aquarium enthusiasts.


The Penguin Tetra, scientifically known as Thayeria boehlkei, is native to the Amazon River tributaries in South America. It is specifically found in Peru and Brazil’s Humboldt current system. The Penguin Tetra got its name from their resemblance. Dr. George S. Myers, an ichthyologist, described this species for the first time in 1944.

Penguin Tetra can be found in habitats with slow-moving water and dense vegetation, such as swamps and backwaters. They prefer shallow waters and can be found in large schools.

The Penguin Tetra is a species that is considered to be relatively hardy and adaptable, making it a popular choice among fish enthusiasts. 

Furthermore, their peaceful nature and appealing appearance make them an excellent addition to any community tank. However, it is important to note that these fish are new to the aquarium trade and are still scarce. Nonetheless, they are becoming more popular in the hobby and can now be found in many pet stores and online.


The Penguin Tetra is named after its distinctive black and white markings, which resemble the appearance of a penguin. These fish have a silver-white body with a black lateral line running along the length of the fish from the snout to the base of the tail. They also have black fins, except for their transparent pectoral fins. 

Juveniles and young adults have a bright white body with a black lateral line beginning at the snout that is less distinct than in adults. They have a large dorsal fin and a small, triangular caudal fin, which allows them to move through the water quickly and easily.

The Penguin Tetra is quite unique among fish species in terms of coloration. Their black and white markings create an eye-catching contrast, making them stand out in any tank. The colors of the Penguin Tetra will be vibrant and striking when kept in a well-maintained tank with proper lighting.


The Penguin Tetra is a small fish species, typically reaching a maximum length of about 2 inches (5 cm). These fish are well-suited to life in a smaller tank due to their compact size and streamlined body shape. 

It’s important to note that the Penguin Tetra’s size can vary depending on various factors, including diet and overall health. Fish that are well-cared for and fed a nutritious diet will typically reach their full-size potential, whereas fish that need to be properly cared for may not reach their full-size potential.

The Penguin Tetra is a relatively fast-growing species in terms of growth rate. Within a year, juveniles and young adults will have reached adult size. They can, however, live in captivity for several years if properly cared for.


Like most fish species, the Penguin Tetra has distinct physical characteristics that allow males and females to be distinguished. Males are generally smaller and slimmer than females, with a more pointed dorsal fin. Conversely, females are more prominent, rounder, and have a more rounded dorsal fin.

Males and females of the Penguin Tetra species have similar coloration patterns, but females have more intense coloration. They have a plumper belly, which is visible during the breeding season. It’s important to note that the differences between males and females can be subtle, and correctly sexing these fish may require some practice. 

However, with a bit of practice and observation, determining the gender of your Penguin Tetra will become easier. It’s also important to keep a good ratio of males and females in a community tank, as these fish are known to breed in captivity. They are simple to produce and a great way to supplement your fish collection without buying new fish.


The Penguin Tetra is known for its timid and peaceful behavior, making it an excellent addition to any community tank. These fish are not aggressive and will not harm their tankmates. They swim in small groups and are active swimmers, constantly on the move and exploring their surroundings. They are most active during the day and least active at night.

Penguin Tetras are also known for their timidity, often hiding behind plants or other decorations when threatened or stressed. This is why providing plenty of hiding places in their tank is important. Penguin Tetras are a schooling species that perform best when kept in groups of at least six or more. They are also known to form close-knit groups within the school and to swim in unison. They are very peaceful and can coexist with other peaceful fish species.

It’s important to note that a Penguin Tetra’s behavior can be influenced by factors such as tank conditions, diet, and overall health. Fish that are well-cared for and given adequate living conditions typically exhibit healthy and normal behavior.


When it comes to tankmates for the Penguin Tetra, it’s important to choose fish that have similar water requirements and are of a similar size. These fish are calm and can coexist with other peaceful fish species, such as:

It’s also worth noting that Penguin Tetras are schooling fish, so keep them in groups of 6 or more to keep them comfortable and stress-free. Keep them away from more prominent or aggressive fish because they may become aggressive toward the Penguin Tetras.

Tank conditions

The Penguin Tetra is a relatively hardy species that can tolerate many water parameters in aquariums. To ensure your fish’s health and well-being, it’s critical to provide them with conditions that are as close to their natural habitat as possible.

A minimum tank size of 20 gallons is recommended for a school of six Penguin Tetras. The larger the tank, however, the better because it will give them more space to swim and explore. Penguin Tetras are native to the warm waters of South America and prefer water temperatures ranging from 72 to 82 degrees Fahrenheit (22 to 28 degrees Celsius). It is important to keep a consistent temperature and to monitor it with a thermometer.

Penguin Tetras prefer a pH range of 6-7 and a water hardness range of 4-20 dGH when it comes to water hardness and pH. It is critical to test the water regularly to ensure that these parameters are within the acceptable range.

They require a good filtration system to keep their water clean and well-oxygenated. A power filter or canister filter would be ideal. It is also important to perform regular water changes to remove any waste and toxins that may have accumulated in the tank.

Penguin Tetras prefer a well-planted tank with plenty of hiding places for decoration. They also work well with fine-leaved plants such as Java moss and floating plants such as duckweed.


Penguin Tetras are not picky eaters and will accept a wide variety of foods. Commercial flakes or pellets, as well as live or frozen foods such as brine shrimp, daphnia, and bloodworms, can be fed to them. Providing a varied diet to ensure proper nutrition and fish health is essential.

It’s also worth noting that Penguin Tetras are small fish and should be fed small meals throughout the day rather than a large meal at the end of the day. This will help to prevent overfeeding and maintain a healthy level of water quality in the tank.


Breeding Penguin Tetras can be difficult because they are not commonly produced fish in captivity. To breed Penguin Tetras, you must have a separate breeding tank with a pH of 6.0 to 7.0 and a temperature of 74-78°F.

A dark, fine-grained substrate and plenty of hiding places, such as caves, rockwork, or plants, should also be included in the tank. Penguin Tetras are egg-scatterers, which means the female will lay her eggs in different places, and the male will fertilize them. Because the eggs are not adhesive and will fall to the bottom of the tank, a breeding mop or fine-leaved plants should be provided to catch the eggs.

Removing the adults from the breeding tank after breeding is best because they may eat the 

eggs or fry. The eggs will hatch in 24-36 hours, and the fry will swim freely in a few days.


Finally, knowing any diseases that may affect Penguin Tetras is critical. These fish are generally hardy and disease-resistant, but they can still become ill if their tank conditions are not ideal. Ich, fin rot, and swim bladder disorder are some of the most common diseases that can affect Penguin Tetras. 

Ich is a parasitic infection that causes white spots on the fish’s skin and fins. Fin rot is a bacterial infection that causes frayed and discolored fins. Swim bladder disorder is a condition that impairs the ability of a fish to control its buoyancy. 

It is important to maintain proper water quality and temperature and provide a balanced diet to prevent these diseases. If your Penguin Tetras show any signs of illness, it is best to consult a veterinarian or a fish expert for proper diagnosis and treatment. Monitoring their behavior is also essential, as sudden changes can indicate an underlying problem. Your Penguin Tetras will thrive with good care and attention, adding a lot of joy and beauty to your tank.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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