Maximum size : 6 cm

Penguin Tetra - Thayeria boehlkei : Complete Fish Profile & Care Guide

Table of contents


The Penguin Tetra (Thayeria boehlkei) is not only a beautiful but also a fascinating fish to observe. Their unique swimming and resting motions, combined with their striking appearance, make them stand out in any aquarium. As a peaceful and hardy species, they are an excellent choice for beginners or experienced hobbyists looking to add some liveliness to their tank.

Penguin Tetras, recognized as a gregarious species, necessitate group maintenance comprising no less than 6 individuals. Appropriate tankmates for Penguin Tetras are those characterized by their tranquillity and peaceful disposition. Species such as Hemigrammus or Hyphessobrycon Tetras, Pencilfish, Dwarf Cichlids, Dwarf Barbs, and Rasboras are well-suited companions. Additionally, Penguin Tetras can coexist harmoniously with Shrimp, Snails, Corydoras Catfish and Loaches. Given their propensity for occasional fin-nipping behaviour, it is advisable to refrain from housing them alongside long-finned tankmates.

Penguin Tetras constitute an excellent enhancement to an extensively planted aquarium adorned with driftwood roots, branches, and meticulously positioned smooth rocks and stones. Optimal aesthetics are achieved through the utilization of a dark substrate, complemented by the inclusion of floating plants to cater to the preferred shaded environment for these fish. While slightly diffused or subdued lighting is favoured, it is acknowledged that this lighting regime might not be conducive to robust aquatic plant growth. However, the introduction of resilient plant species adapted to low-light conditions can be considered to craft a visually appealing and sustainable exhibit. High-quality filtration is also required to maintain water quality. 

The Penguin Tetra is typically greyish-silver in colour, with a striking thick black line running down the lateral and into the lower lobe of the caudal fin. Their belly is silver, providing a stunning contrast to the rest of their body.

Penguin Tetra Photos

Sexual Dimorphism

Discerning between male and female Penguin Tetras is a process of discernible simplicity. Upon attaining maturity, male specimens conspicuously showcase hues that are more vibrant and pronounced in intensity compared to their female counterparts. Furthermore, females tend to manifest a more rounded and plump abdominal region, accompanied by a relatively subdued colouration.

Featured Male
Featured Female
Female Male

Quick Facts

Scientific NameThayeria boehlkei
Year Described1957
Other NamesHockey Stick Tetra and Blackline Tetra
OriginsPeru , Brazil
Max Size6 cm
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 5+
Diet & FeedingOmnivore
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.0 - 8.0
GH 4 -18
TDS 71.43 - 32
Ideal Temperature
72 - 82
22 - 27

Natural Habitat

The Penguin Tetra originates from the pristine waters of the Upper Amazon River Basin and Araguaia Rivers in South America. These captivating fish can be found in small freshwater streams and rivers, which are often adorned with lush vegetation and smooth river rocks. The riverbeds are typically covered with small stones, driftwood roots, and a dark sandy substrate - creating the perfect environment for these striking creatures to thrive. 

 Araguaia River - Brazil
Brazil Flag


To initiate the breeding process of Penguin Tetras, a dedicated softwater breeding aquarium should be established, thoughtfully furnished with an abundance of delicate, fine-leaved plants. The act of spawning unfolds within dimly illuminated surroundings, wherein a substantial number of approximately 1000 eggs are meticulously laid. Once the female has expended her egg supply, prudent practice dictates the removal of the parental figures.

Subsequently, the eggs are poised to hatch within a span of 24 hours. The ensuing fry, characterized by their diminutive size, necessitate the provision of infusoria as their inaugural sustenance. It merits consideration that numerous breeders of this species advocate for the execution of a partial water exchange post-spawning. This measure is advised to mitigate potential water contamination due to the substantial expulsion of milt by the male, which possesses the propensity to compromise the water quality of the breeding environment.

Diet & feeding

Penguin Tetras display an omnivorous dietary inclination and readily embrace an assortment of commercially available sustenance, encompassing flakes, granules, and pellets. Augmenting their nutritional intake, live and frozen fare such as brine shrimp and bloodworms can be judiciously incorporated.

Recognizing their diminutive oral anatomy, it is imperative to select appropriately sized food items to facilitate effective digestion. Complementing prepared nourishment, the inclusion of algae and assorted vegetable components furnishes indispensable nutrients. The adoption of a diversified dietary regimen serves to foster robust vitality and comprehensive well-being in these specimens.

Other Tetras of interest