Maximum size : 6 cm

Redfin Penguin Tetra - Thayeria sp : Complete Fish Profile & Care Guide

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The Red Fin Penguin Tetra (Thayeria sp), a newly discovered member of the Penguin Tetra family, boasts a peaceful disposition, making it unsuitable for boisterous or larger tankmates. Keeping them with other South American fish is advisable to create a harmonious environment. Schooling fish by nature, Red Fin Penguin Tetras thrive when kept in groups of at least six individuals, surrounded by other fish of the same species. Maintaining sufficient numbers may prevent fin-nipping behaviour, as the fish tend to focus on squabbling amongst themselves. However, keeping them in a school also maximizes their ornamental value.

For an optimal aquarium setup, consider crafting a habitat that replicates the Amazonian biotope. To achieve this, utilize river sand as the substrate, incorporate driftwood roots or turtle woods, and introduce dried oak or beech leaves. To further emulate the characteristics of the Amazonian environment, you can employ a peat filter system, which simulates blackwater conditions rich in tannins, a hallmark of this biotope. In such installations, lighting should be subdued, either through lower intensity or diffused by floating plants. The selection of aquatic flora should be guided by the specific requirements of low-light conditions inherent to this biotope replication.

Olive bodies and silver abdomens are typical characteristics of Red Fin Penguin Tetras, with a black line running down the side of the tail fin. The Red Fin Penguin Tetra boasts fiery red fins and a champagne gold-like body colour, greatly enhancing its aesthetic appeal.

Redfin Penguin Tetra Photos

Sexual Dimorphism

Distinguishing between male and female Red Fin Penguin Tetras poses a significant challenge as both sexes boast equally stunning body colouration, which is undoubtedly an advantage of this species. However, during the spawning period, females tend to develop more significant and rounder stomachs, which may aid in discerning them from the males.

Quick Facts

Scientific NameThayeria sp
Other NamesNone
Max Size6 cm
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 6+
Diet & FeedingOmnivore
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 5.5 - 8.0
GH 5 - 20
Ideal Temperature
73 - 82
22 - 27

Natural Habitat

The Red Fin Penguin Tetra, a captivating species, hails from the Upper Reaches of Rio Teles Pires in Brazil, specifically the Guaranta do Norte region, in South America. These fascinating fish dwell in slow-moving wetlands, luxuriously adorned with underwater plants, as well as jungle streams and rivers, replete with dense vegetation but with little aquatic plant life.


Breeding Red Fin Penguin Tetras is a relatively straightforward process, albeit requiring a separate breeding tank to obtain a high yield of fry. This tank should be dimly lit, with fine-leaved plants like java moss or spawning mops providing a suitable surface for the fish to deposit their eggs. Alternatively, a mesh-covered bottom may prevent adults from reaching the eggs, facilitating their development.

Raising the temperature a few degrees higher than the average aquarium temperature can encourage spawning, while the use of peat filtration or RO water is optional. A small air-powered sponge filter is sufficient for filtration purposes. Spawning these fish in a group of six individuals of each sex, following conditioning with small live foods, can prove beneficial. Alternatively, spawning them in pairs entails conditioning females and males separately in different tanks, selecting the best-coloured male and the fattest female, and transferring them into the spawning tank in the evening. They should then spawn the next morning, with a single female capable of producing many eggs.

Regardless of the chosen method, removing the adults after spawning is crucial, as they may consume the eggs and fry. Eggs typically hatch within 12 to 24 hours, with the fry becoming free-swimming three to four days later. Therefore, feeding them with an infusoria type of food is advisable during the initial stage, followed by brine shrimp nauplii or microworms. As both the eggs and fry are light-sensitive, maintaining a dark tank environment is crucial during the early stages of life.

Diet & feeding

Red Fin Penguin Tetras are not a finicky species, accepting most food offerings. However, to promote optimal health and vibrant colours, regular feeding of small live and frozen foods, such as artemia, bloodworm, and daphnia, along with high-quality dried food, like flakes and granules, is advisable.

Other Tetras of interest