Penguin Tetra Care: An Overview on Tank Mates, Water Parameters, and More

penguin tetra Thayeria boehlkei
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Last Updated: September 4, 2023 by Flora Gibbins

Did you know that the Penguin Tetra has a unique swimming style that sets it apart from other fish? Instead of swimming with their bodies positioned horizontally, like most fish do, Penguin Tetras swim with their bodies slightly tilted upward. This intriguing behavior, combined with their unique appearance and lively personalities, makes them fascinating to watch and thus a popular choice among aquarium geeks.

In this article, we’ll dive deep into the world of Penguin Tetras. I’ll tell you all about their origin, care, and everything in between. Let’s swim right into it!

Penguin Tetra Facts and Overview

  • Common names: Penguin Tetra, Penguin Fish, Blackline Penguinfish, Blackline Thayeria, and Hockey Stick Tetra
  • Scientific name: Thayeria boehlkei
  • Adult size: Up to 3 inches (7.5 cm) in length
  • Lifespan: Approximately 5-8 years in a well-maintained aquarium
  • Colors and Markings: Silvery body with a subtle golden hue, vertical black stripe running from the base of the dorsal fin to the tail, and translucent fins
  • Origin: Native to the Amazon River Basin in South America, primarily in Peru and Brazil

Origin and Distribution

Penguin Tetras are native to the Amazon River Basin in South America, with a significant presence in Peru and Brazil. They inhabit slow-moving rivers and streams, as well as floodplain lakes and other water bodies with dense vegetation. The natural habitat of Penguin Tetras features clear to slightly murky water, a soft substrate, and an abundance of aquatic plants and hiding spots.

The species was first described by James E. Böhlke in 1954, and since then, it has gained popularity in the aquarium trade due to its distinctive appearance and easy-going nature. Over the years, the demand for Penguin Tetras has led to commercial breeding programs, ensuring a steady supply of these fish for the global aquarium market. As a result, most Penguin Tetras available today are tank-bred rather than wild-caught.

In their natural environment, Penguin Tetras form schools and coexist peacefully with a variety of other fish species. This schooling behavior, coupled with their adaptability and peaceful temperament, makes them an excellent choice for community aquariums.


Let’s talk about the unique appearance of Penguin Tetras that makes them stand out in any aquarium. Their bodies are primarily silver, sometimes with an olive cast, which adds a subtle touch of color to their elegant profile. But what really sets them apart is that thick, signature black stripe running from behind their eye all the way to where it meets the tail, where it slants down along the bottom tail fin. This makes it look like a hockey stick and why some call this species the Hockey Stick Tetra.

In addition to that awesome stripe, Penguin Tetras have translucent fins that catch the light as they move through the water, which I find really pretty. Their dorsal fin is relatively short, while their anal fin is elongated, giving them a streamlined appearance that contributes to their speed and agility.

Penguin Tetras can grow up to 3 inches (7.5 cm) in length, making them slightly larger than many other tetra species. The combination of their unique black stripe, silver body, and graceful fins creates a captivating display in any aquarium, especially when they’re swimming in a school of six or more individuals. As you can see, the appearance of Penguin Tetras truly sets them apart from other fish, making them a favorite choice for aquarists looking to add a touch of flair to their tank.

Temperament and Behavior

Now that we’ve covered the tres chic appearance of Penguin Tetras, let’s get a little bit into what their vibe is in the tank. These little fish are known for their peaceful and social nature, making them ideal for community aquariums.

One of the most awesome aspects of Penguin Tetras is their schooling behavior. In the wild, they form schools for safety and socialization, and they exhibit the same behavior in aquariums. It’s important to keep a group of at least six Penguin Tetras in your tank, as this will help them feel more secure and comfortable. I say, the more, the merrier! Watching a group of these fish swim together is truly mesmerizing, and that unique slightly upward tilted swimming posture I mentioned earlier, only adds to the interest.

Penguin Tetras are also known for their playful and curious personalities. They’ll often explore every nook and cranny of their environment, swimming in and out of plants and decorations. Their active nature means they’ll dart around the tank, adding a sense of liveliness to your aquarium. However, despite their energetic demeanor, they are not aggressive and will coexist peacefully with other compatible tank mates.

Penguin Tetra Tank Mates

As I said, Penguin Tetras are peaceful, social fish that do amazingly in a community aquarium, provided you choose the right tank mates. Let’s take a look at some compatible companions for them and those that are best avoided.

Compatible Fish Species

Penguin Tetras get along well with other peaceful, similarly-sized fish. Some suitable tank mates include:

  • Other easygoing Tetra species, such as Cardinal Tetras, Gold Tetras, Silver Tetras, and Flame Tetras
  • Corydoras catfish
  • Small to medium-sized rasboras
  • Gouramis (smaller, peaceful species)
  • Dwarf Cichlids, like Apistogramma or Kribensis
  • Hatchetfish
  • Livebearers, such as guppies, mollies, and platies

Non-Fish Tank Mates

In addition to compatible fish species, Penguin Tetras can also share their tank with some non-fish aquatic creatures. Some examples include:

  • Freshwater shrimp, like Red Cherry Shrimp or Amano Shrimp
  • Freshwater snails, such as Nerite Snails or Mystery Snails

Tank Mates to Avoid

While Penguin Tetras are adaptable and get along with many tank mates, it’s crucial to avoid aggressive or much larger fish that may view them as prey. Some examples of tank mates to avoid include:

  • Larger, aggressive cichlids, like Oscars or Jack Dempseys
  • Aggressive or territorial species, like Tiger Barbs or Red-Tailed Sharks
  • Large, predatory fish, such as Arowanas or Pictus Catfish

penguin tetra school

Penguin Tetra Care

Aren’t you in love with them yet? It’s time for me to tell you what it’s like to live with these guys and what goes into taking care of them so they thrive in your aquarium. In this section, we’ll cover everything from their dietary needs to maintaining optimal water parameters and their common health issues.

Tank Setup

Creating the perfect environment for your Penguin Tetras is crucial for their well-being and happiness. While they’re not high-maintenance divas about where they live, Penguin Tetras do have their minimum standards.

Tank Size

Penguin Tetras are active swimmers and they need space to move around. A minimum tank size of 20 gallons is recommended for a small school of six Penguin Tetras. However, if you plan on adding more fish or creating a community aquarium, consider a larger tank of 30 gallons or more to provide everyone with enough room.

What to Put in the Tank

To replicate the natural habitat of Penguin Tetras, it’s essential to include the following elements in your tank setup:

  • Substrate: Use a soft, sandy substrate to mimic the riverbeds they naturally inhabit. This will also be more comfortable for any bottom-dwelling tank mates, such as Corydoras catfish.
  • Plants: Add live aquatic plants, like Java Fern, Amazon Swords, or Anubias, to provide hiding spots, promote a sense of security, and improve water quality. You can also use floating plants, like Water Sprite or Frogbit, to create shaded areas.
  • Hardscape: Incorporate driftwood, rocks, or other decorations to create additional hiding spots and make the tank visually appealing.

Equipment and Accessories

In addition to the tank and decorations, you’ll need the following equipment and accessories to maintain a healthy environment for your Penguin Tetras:

  • Filter: Choose a high-quality filter to ensure proper water circulation and filtration. A gentle flow is best, as Penguin Tetras prefer slow-moving water.
  • Heater: Maintain a stable water temperature with an adjustable heater. Penguin Tetras thrive in water temperatures between 72°F and 79°F (22°C to 26°C).
  • Thermometer: Use an aquarium thermometer to monitor the water temperature regularly and ensure it remains within the ideal range.
  • Lighting: Moderate lighting is suitable for Penguin Tetras. Ensure there’s a consistent day and night cycle to prevent stress.
  • Water testing kit: Regularly test water parameters, such as pH, ammonia, nitrite, and nitrate levels, to ensure they stay within the optimal range for your fish.

Water Parameters

Now that we’ve covered tank setup, let’s chat about water parameters. Don’t worry; I’ll try not to bog you down with the technical stuff.

Penguin Tetras are pretty adaptable, but there are a few key factors to keep in mind when it comes to maintaining their ideal water conditions:

  • Temperature: As I mentioned earlier, these guys prefer a water temperature between 72°F and 79°F (22°C to 26°C). Consistency is crucial, so make sure your heater and thermometer are working well to avoid temperature fluctuations that can stress your fish.
  • pH: Penguin Tetras like their water slightly acidic to neutral. Aim for a pH level between 6.0 and 7.5. Regularly testing the pH and making adjustments as needed will keep your fish feeling their best.
  • Hardness: These little swimmers prefer soft to moderately hard water. A general hardness (GH) of 2 to 12 dGH and a carbonate hardness (KH) of 3 to 10 dKH is ideal.
  • Ammonia, Nitrite, and Nitrate: Maintaining good water quality is essential for the health of your Penguin Tetras. Keep ammonia and nitrite levels at 0 ppm (parts per million), and try to keep nitrate levels below 20 ppm. Regular water changes and routine filter maintenance will go a long way in achieving this.

Speaking of water changes, it’s a good idea to replace around 25% of the tank water every couple of weeks. This helps to keep the water clean and stable, ensuring a healthy environment for your fish.

See, that wasn’t so bad, right?

Diet and Feeding

Feeding your Penguin Tetras a well-balanced and varied diet is essential for their health and vitality. In this section, we’ll explore their dietary needs and best practices for feeding these charming little fish.

In the wild, Penguin Tetras are omnivorous, feeding on small insects, crustaceans, and plant matter. To replicate this natural diet in your aquarium, it’s important to provide them with a mix of high-quality commercial foods and occasional treats.

  • Flake or Pellet Food: Choose a high-quality flake or micro-pellet food formulated for small tropical fish as the staple of their diet. This will ensure they receive the essential nutrients they need for proper growth and health.
  • Frozen and Freeze-Dried Foods: Supplement their staple diet with a variety of frozen or freeze-dried foods, such as brine shrimp, daphnia, bloodworms, and tubifex. These protein-rich treats will help enhance their coloration and promote overall well-being.
  • Live Foods: You can also occasionally offer live foods, like live brine shrimp, blackworms, or mosquito larvae, to provide enrichment and mimic their natural feeding behavior.

When it comes to feeding your Penguin Tetras, a little goes a long way. Feed them small portions, about what they can consume in 1 to 2 minutes, once or twice a day. Be careful not to overfeed, as this can lead to poor water quality and health issues.

Common Health Issues and Diseases

Penguin Tetras, like all fish, can be susceptible to certain health issues and diseases. Being aware of these potential problems and taking steps to prevent them can help ensure your fish live a long and healthy life. In this section, we’ll discuss common ailments that can affect Penguin Tetras and how to address them.

  • Ich (White Spot Disease): Ich is a common parasitic infection that causes small white spots to appear on your fish’s body, fins, and gills. If you notice these symptoms, increase the water temperature to 82°F (28°C) for a few days and treat the tank with a medication designed for Ich. Remember to remove any activated carbon from your filter before treatment.
  • Fin Rot: Fin rot is a bacterial infection that causes the fins to become ragged and discolored. To treat fin rot, improve water quality through regular water changes and consider using a medication specifically formulated for treating bacterial infections in fish.
  • Swim Bladder Disease: Swim bladder disease can cause your fish to have difficulty swimming or maintaining buoyancy. This condition can be caused by overfeeding, constipation, or infection. To address swim bladder issues, feed your fish a diet that includes high-fiber foods, such as daphnia or blanched peas, and consider adjusting your feeding schedule.

Prevention is key when it comes to maintaining the health of your Penguin Tetras. Regular water changes, proper filtration, a balanced diet, and monitoring water parameters are crucial for keeping your fish in tip-top shape.

Breeding Penguin Tetras

So, breeding Penguin Tetras can be a really cool experience if you’re into the whole aquarist thing. And honestly, who wouldn’t want a tank full of adorable little baby fish swimming around? To get started, you’ll need a separate breeding tank or a partitioned section of your main aquarium.

Once you’ve got your setup ready, you’ll need to condition your breeding pair with some high-quality, protein-rich food and gradually increase the temperature to around 80°F (27°C). This will help get them in the mood, so to speak.

When your pair is ready, it’s time to provide them with a spawning site, like some Java moss or a breeding cone. The male will start to court the female, and once she’s ready to spawn, they’ll swim together around the site, releasing eggs and sperm. It’s like a little fishy romance!

After spawning, it’s important to remove the adult fish from the breeding tank to prevent them from eating the eggs. The eggs will hatch in about 24 to 36 hours, and the fry will become free-swimming after a few more days.

Some tips to keep in mind when breeding Penguin Tetras: provide a suitable breeding site, maintain water quality, use a breeding pair, and monitor for spawning behavior.

Related Species

Penguin Tetras are just one of the many species of tetras out there, and if you’re a fan of these charming little fish, you might be interested in exploring some of their close relatives. In this section, we’ll take a look at some of the related species to Penguin Tetras.

  • Neon Tetra: Perhaps one of the most iconic tetras, the Neon Tetra is known for its striking blue and red coloring. Like Penguin Tetras, Neons are peaceful, community-oriented fish and are popular choices for planted aquariums.
  • Cardinal Tetra: Another popular species, the Cardinal Tetra is similar in appearance to the neon tetra, but with a larger, more prominent red stripe. They prefer slightly softer water than Penguin Tetras and are also known for their peaceful temperament.
  • Rummynose Tetra: With its distinctive red head and white and black striped body, the Rummy Nose tetra is a colorful and active addition to any community aquarium. They are shoaling fish and do best in groups of six or more.

penguin tetra school


Here are some frequently asked questions about Penguin Tetras:

Are Penguin Tetras fin nippers?

No, Penguin Tetras are generally peaceful and don’t exhibit fin-nipping behavior. However, they may nip at the fins of slow-moving or long-finned fish, so it’s best to avoid keeping them with species that have long, flowing fins.

Can Penguin Tetras jump out of the tank?

Yes, like many fish, Penguin Tetras are capable of jumping out of their tank. To prevent this, make sure your aquarium has a secure lid or cover.

How many Penguin Tetras should I keep in my tank?

Penguin Tetras are social fish and do best in groups of six or more. Aim for at least 10 gallons of water per fish to provide ample swimming space.

Do Penguin Tetras need a specific type of substrate?

No, Penguin Tetras are adaptable and can do well with a variety of substrates, including sand, gravel, or planted substrates. Just make sure the substrate is compatible with the plants and other fish in your tank.

Are Penguin Tetras Right for Your Aquarium?

Remember, taking care of aquarium fish requires patience, attention, and a willingness to learn. With the right care and attention, your Penguin Tetras will reward you with their delightful swimming patterns and peaceful presence.

Penguin Tetras are so cool and unique and I’m sure they are sure to be a beloved addition to your aquatic family.

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