Penguin Tetra 101: Care, Diet, Tank Size, Tank Mates, & More

Do you have a Penguin Tetra? If you do, you’re probably wondering what kind of care it needs. Well, wonder no more! From what kind of food they eat to how often they need to be fed, we’ve got you covered.

Take a few minutes of your time to learn all there is to know about caring for your Penguin Tetra.

Penguin Tetra Swimming
Penguin Tetra

Species Summary

The Penguin Tetra (Thayeria boehlkei) is a peaceful species found in tributaries and floodplains of the upper Amazon River basin in Peru and around the Araguaia River in Brazil. The Araguaia crosses several states in Brazil and is supposed to have many springs due to the high number of tributaries that flow into it.

This fish can be found in different habitats, varying from wetlands with lush vegetation of underwater plants to jungle streams with dense vegetation along the banks. 

The life expectancy is around five years, and it usually lives in groups. This fish is also is known to occupy the upper and middle regions of an aquarium but can also be found swimming and feeding on the bottom. It is characterized by its way of swimming, as it does so at an angle. This feature, along with its white stripe, gave this fish its popular name.

And it gets better, the Tetra Penguin is not a fussy eater and will accept most foods available to ornamental fish, including high-quality flake and live feeds.

Penguin Tetra Care Guide

If you’re new to caring for a Penguin Tetra, read on to learn how to set up your fish tank. Once you have your tank ready, it’s time to learn about your Penguin Tetra’s specific needs.

Tank Size

To ensure the comfort of a small group of Penguin Tetras, the aquarium should be a minimum of 15 gallons. These fish are good swimmers and will enjoy the extra space to move around.

It is important to remember that community aquariums will require more space and extending shoals.

Tank Mates

Tetra Penguins must cohabitate only with other gentle fish that are not much larger than them in size due to their peaceful nature. It is essential to keep at least ten specimens in a school so that they show their natural behavior and more enhanced colors.

Penguin Tetras are most compatible with fellow South American fish species, such as Hemigrammus or Hyphessobrycon Tetras, Apistogramma, and other small cichlids such as Corydoras and loricariid (plecos).

In a non-South American community aquarium, you can combine it with smaller Rasboras, Barbs, Anabantoids, and West African Dwarf Cichlids such as Pelvicachromis.

Same Species Tanks

While the Penguin Tetra is not commonly used in species-only aquariums, it can produce a remarkable effect in a densely planted aquarium with a dense aquatic landscape.

Water Parameters

This fish is highly adaptable to different water conditions due to the fact that almost all commercial fish are mass-bred in captivity. It can thrive in different water conditions, whether soft and acidic or harder and more alkaline (pH 5.5 to 8.0).

The temperature should be maintained at 71 to 82 degrees Fahrenheit. Water hardness is of little importance with this Characidae; anything between 5 and 19 dH is acceptable.

This fish can withstand a reasonably wide pH and hardness range; however, it requires acidic and very soft water (GH < 3, KH < 3) for reproduction. And as the Penguin Tetra is a good swimmer, it requires a considerable amount of open space in an aquarium of no less than 75 liters.

What to Put in Their Tank

It is best to keep the aquarium well planted, with plenty of rocks, driftwood, and roots to mimic its natural habitat. Add a dark substrate and some floating plants to create a well-shaded environment for these fish.

You must leave free spaces in the aquarium, even if there is a lot of vegetation, so the animals can swim freely and not encounter obstacles. 

A biotope aquarium can be created by using a river sand substrate and adding dark wood roots. Dried leaves can also be added to complement the natural feel.

Leave the wood and leaves to color the tank water the color of weak tea. A small bag, net filled with aquarium peat, can be added to the filter to help simulate black water conditions. Be careful to maintain a good water maintenance routine to avoid adverse effects.

Common Diseases

The Penguin Tetra is so special because they are incredibly hardy and rarely get sick. This makes them ideal for anyone who wants an easy fish to take care of.

Bacterial infections, external parasites, and fungi are the main among the various diseases that can affect these fish when their immune system is compromised.

Food and Diet

The Penguin Tetra is an omnivorous species which preys on various insects, worms, crustaceans, and small invertebrates. However, it will accept almost anything that is offered in an aquarium setting.

To keep your fish healthy and full of color, it is best to offer high-quality feed daily, along with fresh, live foods such as bloodworms, daphnia, and brine shrimp.


The species has a life expectancy of around five years.

But remember this: your animal’s lifespan is directly related to factors such as water quality, and food availability.


The classic tetra shape is seen in the Penguin Tetra, with a long silvery body that shows an iridescence concerning light, most notably near the gills. The ends are yellowish, translucent, and have a white glow; they may also appear slightly bluish at the tips. 

The black stripe begins just behind the fish’s head, continuing to the base of its tail. At this point, the stripe swerves and follows along the underside of the tail to its end.


The maximum length that has been reported is up to 6 cm. Although the Penguin Tetra is listed for sale by some sources as measuring just 1.2 in, it can be quickly seen that this fish grows significantly larger than that.

Behavior and Temperament

The Tetra Penguin is generally considered a very peaceful fish, but it is thought to feel safer in groups. The bigger the shoal, the more natural their behaviour appears, and colors are more vivid.

Like other tetras, it is a species that forms a free hierarchy and can be kept in a community aquarium with small-sized fish. You’ll love that these peaceful species do not compete well with restless tankmates.

The fin-nipping behavior, which is sometimes attributed to this species, usually does not manifest when kept in sufficient numbers, as this species tends to focus on fighting among themselves. Like most tetras, it looks a lot easier when kept that way.


Breeding the Tetra Penguin is not difficult, although you will need a separate aquarium if you want to raise as much fry as possible.

The aquarium should be dimly lit and contain plenty of thin-leaved plants, such as java moss, to provide fish with a place to lay their eggs. Contrary to what is usually used in the main aquarium, the water should be slightly acidic, and the temperature should be increased, as this helps with spawning.

You can add to this aquarium a small group formed by half a dozen species of each sex. Then, condition them with an abundance of live foods so that spawning occurs without any significant problems. However, if you want to spawn using only a couple, you must condition them in groups of males and females in separate aquariums. When the females are full of eggs and the males are showing their best colors, select the chubby and the most colorful male and transfer them to the breeding tank at night. Spawning should take place the following day.

A female can produce up to 3,000 eggs, although 1,000 is the more common number. In some cases, males can release so many gametes into the water that it may be necessary to carry out a partial water change in the aquarium.

In either breeding situation, the adults will eat the eggs if given the opportunity and should be removed as soon as they are laid. Eggs hatch in 12 – 24 hours, but the fry will be free swimming around the aquarium in about 3-4 days.

Eggs and fry are sensitive to light in the early stages of life, so the aquarium should be kept in the dark location if possible.

Gender Differences: Male vs Female

Females tend to have slightly larger and more plump bodies compared to males, especially in the ventral region. Adult males typically have thinner bodies and display more strong coloration.

Penguin Tetra Fun Facts

  • All species of the genus Thayeria are known as Penguin Tetra; Thayeria boehlkei is by far the most popular in the aquarium trade, although T. obliqua is equally attractive.
  • The species are easy to differentiate; in Thayeria boehlkei, a black stripe extends along almost the entire side of its body, from the gill opening to the caudal fin. In T. obliqua, this stripe disappears entirely before reaching the dorsal fin region.
  • In the third species, T. ifati, the black stripe is present only on the upper part of the lower caudal lobe extending above its lateral line beyond the dorsal fin. T. ifati, when exposed in good conditions, the dorsal and anal fins develop red tips.
  • These fish swim in an oblique style, with the head, turned slightly upwards, a behavior typical of all species of the genus. That’s why theyare also called oblique tetras.


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