Penguin tetra
Thayeria boehlkei
Also known as blackline penguinfish
Care at a glance
- Temperature
- 72–82°F (22–28°C)
- pH
- 6.0–7.5
- Adult size
- 2.6 in (6.5 cm)
- Minimum tank
- 20 gal (75 L)
- Temperament
- Peaceful
- Social behavior
- Schooling
- Swim level
- Middle
- Difficulty
- Easy
- Breeding
- Medium
- Rarity
- Rare
- Origin
- Peru, Brazil
- Family
- Characidae
Overview
A peaceful schooling fish, so keep at least six and ideally more. They are active and spend most of their time in the middle and upper water. A tank of around 75 liters or more works, with temperatures in the low to high 20s C and a pH of 6 to 7.5. Feed flake, small pellets, and frozen foods like daphnia and bloodworms, and they mix well in a calm community.
In the wild
Penguin tetras live in slow tributaries and streams of the Amazon basin in Peru and Brazil, among leaf litter and submerged plants. The water there is soft and runs from slightly acidic to neutral. A tank with planting, some open swimming room, and gentle flow suits them, and a darker substrate shows their stripe off well.
Good to know
This fish belongs to the Characidae, the tetra family. It grows to roughly 6.5 cm and is named for the bold black stripe that runs back into the lower tail, giving it a penguin look. It is an egg scatterer with no parental care, and the eggs hatch in a day or two. The species is widespread and not considered at risk.
Did you know
Penguin tetras rest and swim at a head-up tilt rather than level. It looks odd at first, but it is normal for the species, not a sign of illness or a swim bladder problem.
Where to buy
Some links may not be the exact species or variety.
- Aquatic Arts Freshwater fish, shrimp and snails with an arrive-alive guarantee
- LiveAquaria Freshwater and saltwater fish, inverts and corals
- Imperial Tropicals Freshwater fish and inverts bred at a Florida hatchery
- Dan's Fish Freshwater fish, shrimp and snails with a live arrival guarantee
- Aqua Huna Freshwater fish, shrimp and plants with a three day live arrival guarantee
…or ask your local fish store.
Appears in
Freshwater fish · Tetras · Beginner fish · Schooling fish · Community fish
Keeping Penguin tetra?
Track water tests, reminders and stocking fit.
Related species

Colombian Tetra
Hyphessobrycon columbianus2.6 in (6.5 cm)20 gal (75 L)73–82°F (23–28°C)
Bleeding heart tetra
Hyphessobrycon erythrostigma2.4 in (6 cm)20 gal (75 L)70–81°F (21–27°C)
Glass bloodfin tetra
Prionobrama filigera2.4 in (6 cm)20 gal (75 L)73–81°F (23–27°C)
Red flush tetra
Hemigrammus stictus2.4 in (6 cm)20 gal (75 L)73–81°F (23–27°C)
Lesser bleeding heart tetra
Hyphessobrycon socolofi2.2 in (5.6 cm)24 gal (90 L)73–82°F (23–28°C)
Cochu's blue tetra
Boehlkea fredcochui2.2 in (5.5 cm)20 gal (75 L)72–82°F (22–28°C)
