The Flag Cichlid (Mesonauta festivus) is a peaceful and visually striking freshwater fish native to South America’s slow-moving rivers, especially the Amazon Basin. Reaching 4.7–6.3 inches in length, they thrive in well-maintained aquariums with stable water conditions, gentle filtration, and plenty of hiding spots like driftwood, rocks, and tall plants. A minimum 40–55 gallon tank is recommended, with water temperatures between 72–82°F and a pH of 6.5–7.5. These social fish do well in groups and can coexist with similarly tempered species, though they may become territorial during breeding. Their diet should include high-quality flakes, pellets, and occasional live or frozen foods. Regular water changes and a secure lid are essential, as Flag Cichlids are known to jump when startled2.
🏳️ Flag Cichlid Care Summary
Attribute
Details
Scientific Name
Mesonauta festivus
Origin
Amazon Basin, South America
Size
4.7–6.3 inches (12–16 cm)
Lifespan
8–10 years
Tank Size
Minimum 40–55 gallons
Water Temperature
72–82°F (22–28°C)
pH Range
6.5–7.5
Temperament
Peaceful; territorial during breeding
Tank Mates
Geophagus, Apistogramma, Barbs, Tetras (avoid very small species)
Substrate
Fine sand or smooth gravel
Plants
Vallisneria, Java Fern, Anubias (avoid delicate species)
Diet
Flakes, pellets, live/frozen foods
Special Notes
Needs hiding spots; secure lid to prevent jumping