Penguin Tetra
Thayeria boehlkei
Description
The Penguin Tetra is a small, attractive fish known for its distinctive appearance and peaceful nature. This species has a slender, streamlined body with a silver to pale translucent base color. The most striking feature of the Penguin Tetra is the dark vertical stripe that runs through its midsection, giving it a “penguin-like” look. The top of the body may have a slightly darker coloration with faint hints of orange or yellow. Males are typically smaller and slightly more colorful than females, particularly when they are displaying or courting. Penguin Tetras are peaceful, social fish that thrive in schools and exhibit coordinated swimming behavior when kept in groups. They are active and enjoy swimming in the middle to upper regions of the tank.
Habitat Origin
Native to the slow-moving rivers and streams in South America, particularly in the Amazon Basin in Brazil. They are found in clear, slightly acidic water with submerged vegetation and moderate water flow. In their natural habitat, Penguin Tetras swim in schools near the surface, often amidst aquatic plants and roots, where they graze on small invertebrates and plant matter.
Aquarium
Ideal Number in Aquarium: At least 6 individuals, as they are schooling fish and feel more secure in groups.
Favorite Food
Penguin Tetras are omnivores and will accept a variety of foods, including high-quality flake food, micro pellets, and live or frozen foods such as brine shrimp, daphnia, and bloodworms. They will also graze on algae and small plant matter in the tank, making them a good addition to planted tanks. A varied diet ensures they maintain their vibrant colors and active behavior.
Behavior:
Penguin Tetras are peaceful, social fish that thrive in groups. They are not territorial and do well in schools of at least 6 individuals, where they feel secure and can display their natural schooling behavior. These tetras are active swimmers and are usually seen darting through the middle and upper parts of the tank. They are calm and non-aggressive toward other species and make great tankmates for peaceful community setups. However, they may become shy or stressed if housed alone or in small groups.
Special Care:
Penguin Tetras thrive in a well-planted tank with plenty of hiding spots, such as rocks, driftwood, and dense plants. A fine gravel or sandy substrate is ideal for them to forage naturally. Regular water changes and good filtration are essential for maintaining water quality, as they are sensitive to poor water conditions. These fish prefer slightly acidic to neutral water conditions and benefit from stable water parameters. While they are not particularly sensitive to water flow, a moderate water flow mimicking their natural habitat is ideal for keeping them healthy and active.
Compatibility with Other Fish:
Yes, Penguin Tetras are compatible with other peaceful species such as tetras, rasboras, and small catfish. They can be housed in community tanks with other non-aggressive fish, but care should be taken to avoid aggressive or large species that may stress them or view them as food. Their peaceful and schooling nature makes them ideal for community aquariums with a variety of small, calm fish. They do well with other species that swim at different levels of the tank.
Breeding Setup
Using a separate breeding tank is highly recommended for Penguin Tetras to prevent egg predation and allow precise control of water conditions. A 40-liter (10-gallon) tank provides sufficient space for adult fish and fry. Maintain a pH between 6.0 and 7.0, temperature between 24–28°C (75–82°F), and general hardness (GH) of 4–10 dGH. A gentle sponge filter is ideal for maintaining water quality without disturbing the eggs or stressing the fish. For the substrate, opt for fine gravel or a bare-bottom tank, and include live plants like Java moss and Hornwort for egg deposition and natural shelter. Keep the lighting moderate to low, as these tetras prefer dim environments similar to their native streams.
Conditioning for Breeding
To prepare Penguin Tetras for spawning, feed them a protein-rich diet of live foods like daphnia, brine shrimp, and bloodworms, supplemented with high-quality flakes or pellets. A balanced diet improves health and increases spawning success. Perform weekly 25% water changes to maintain clean and stable conditions. Good nutrition and pristine water are key to triggering reproductive behavior.
Spawning Process
Penguin Tetras are egg-scattering fish and typically spawn in the early morning or late evening under dim lighting. Males will chase females and exhibit brighter coloration to attract them. A female may lay up to 100 adhesive eggs, which attach to plants, tank glass, or other surfaces. Once spawning is complete, remove the adults promptly to prevent them from consuming the eggs, which is common behavior in this species.
Fry Care
Eggs hatch within 24–36 hours, after which the fry will absorb their yolk sacs before becoming free-swimming. Begin feeding them infusoria, liquid fry food, or microscopic live foods like rotifers. As they develop, introduce baby brine shrimp and finely crushed flakes or shrimp pellets. Perform daily 10–15% water changes to maintain excellent water quality, and keep a close eye on ammonia, nitrite, and nitrate levels. A stable temperature of 24–28°C and soft water will support healthy fry development.
Important Notes
Penguin Tetras reach sexual maturity at around 6–8 months. Males are slimmer and exhibit more vivid coloration, particularly red markings on the fins, while females are fuller-bodied, especially when gravid. To ensure successful breeding, minimize stress by maintaining stable water parameters, avoiding sudden environmental changes, and keeping the breeding tank free of other fish. A calm, controlled environment is essential for both spawning and fry survival.