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False Penguin Tetra

Scientific Name: Thayeria boehlkei
Family: Characidae, Hemigrammus Clade

About the False Penguin Tetra

Species Type: Freshwater Fish
Category: Characins

Care Level: Easy. Does well in a slightly more narrow range of water parameters and shouldn't be used to cycle an aquarium. Will eat most prepared foods. May have some specific care requirements in terms of particular water parameters, social behaviors, food items etc.

Origin: Rio Araguaia in Brazil and the Peruvian Amazon.

Compatibility/Temperament: Peaceful, suitable for a community tank with other characins, rasbora, danio, gourami, angelfish, dwarf cichlids, small catfish and loaches (acid water) or livebearers (basic water).


Of the three species in the genus, this is the most popular and common in the hobby. This species was originally described in the literature as the Penguin Tetra, being confused with the true Penguin Tetra, T. obliqua [see separate Profile], which confusion was resolved when Dr. Stanley Weitzman described and named the subject species in 1957. The photos accompanying the Profiles show the difference between the two species.

Like the other two species in the genus, this one also swims in a head-up position at 45 degrees; it also remains close to the surface among vegetation, preying on insects that fall onto the water. Both traits are shared with the two pencilfish species Nannostomus eques and N. unifasciatus.

Should be kept in a group of six or more in a well-planted aquarium. Tank should be covered as they may jump if given the opportunity. Unlike the other two species in the genus, this species can be maintained in slightly basic (alkaline) water aquaria.

The genus Thayeria was previously considered within the Sub-Family Tetragonopterinae, but this classification has for some time been deemed incertae sedis [Latin for "of uncertain placement"]. In a study published in 2010, it was determined that the Sub-Family Tetragonopterinae should only be used for species within the genus Tetragonopterus. [Robert Javonillo, Luiz R. Malabarba, Stanley H. Weitzman and John R. Burns, "Relationships among major lineages of characid fishes (Teleostei: Ostariophysi: Characiformes), based on molecular sequence data," Molecular Phylogenetics and Evolution, Vol. 54, No. 2 (February 2010)]. Also, J. Marcos Mirande proposed several revisions to the Family Characidae based upon phylogenetic diagnosis in "Weighted parsimony phylogeny of the family Characidae (Teleostei: Characiformes)," Cladistics, Vol. 25, No. 6 (July 2009). Some genera have been moved to a new Sub-Family, while others are now (temporarily) assinged to a specific clade within the Family pending further study.

False Penguin Tetra Diet

A typical characin predator of insects, worms, etc., it will accept most prepared foods and appreciate frozen daphnia and bloodworms or live foods.


Grows to 2.4 inches, possibly up to 3 inches.

Minimum Tank Suggestion

24 inches in length.

Ideal water parameters for False Penguin Tetra

Soft to moderately hard (hardness up to 20 dGH) acidic to slightly basic (pH up to 8.0) water, temperature 22-28C/72-82F.

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