The Redfin Penguin Tetra, scientifically known as Thayeria sp. Rio Teles Pires, is a captivating and relatively rare species of freshwater fish native to the clear, slow-moving rivers and streams of South America, particularly in the Rio Teles Pires region. This species is highly prized by aquarists for its unique appearance, peaceful demeanor, and active schooling behavior, making it an excellent addition to well-maintained community aquariums.

Redfin Penguin Tetras are characterized by their elongated, laterally compressed bodies and striking coloration. Their bodies typically display a shimmering silver base color with a distinctive black stripe running from the middle of their body to the lower half of their caudal fin, which is a common feature of penguin tetras. The "redfin" aspect of their name comes from the vibrant red coloration on their dorsal and caudal fins, which adds a brilliant contrast to their silver bodies. Males are usually more colorful and slender compared to females.

In captivity, Redfin Penguin Tetras thrive in aquariums that closely mimic their natural habitat. A tank setup should include a soft, sandy or fine gravel substrate and plenty of live plants, such as Java moss, Anubias, and Amazon swords, which provide cover and create a comfortable environment. Adding driftwood and rocks can enhance the natural look of the tank and provide additional hiding spots.

Water conditions should be slightly acidic to neutral, with soft to moderately hard water. Maintaining stable water parameters through regular water changes and efficient filtration is crucial for the health and well-being of Redfin Penguin Tetras. They are relatively hardy fish but do best in clean, well-oxygenated water.

Redfin Penguin Tetras are schooling fish that should be kept in groups to promote their well-being and natural schooling behavior. Keeping them in a school not only reduces stress but also enhances their vibrant colors and active swimming patterns. They are peaceful and can be housed with other similarly sized, non-aggressive fish, making them ideal for community tanks.

Their diet should be varied to ensure they receive all necessary nutrients. Redfin Penguin Tetras are omnivorous and will readily accept high-quality flake foods, small pellets, and live or frozen foods such as brine shrimp, daphnia, and bloodworms. Providing a mix of these foods will help maintain their health, vibrant colors, and energetic behavior.

Breeding Redfin Penguin Tetras in captivity can be relatively straightforward under the right conditions. They are egg scatterers, typically laying their eggs among fine-leaved plants or in spawning mops. To encourage breeding, maintain optimal water conditions with slightly acidic, soft water and provide plenty of fine-leaved plants or spawning mops. Once spawning occurs, it is advisable to remove the adults from the breeding tank to prevent them from eating the eggs. The eggs usually hatch within a few days, and the fry can be fed with infusoria or finely crushed flake food until they are large enough to accept standard fare.

Overall, the Redfin Penguin Tetra is an excellent choice for aquarists looking for a small, colorful, and peaceful species. Their striking appearance, gentle nature, and dynamic behavior make them a delightful addition to any well-maintained aquarium. With proper care and the right environment, they can thrive and bring a touch of vibrant beauty and lively activity to your aquatic setup.