Flag Tetra

Geographic Origin and Biotope: Tocantins River basin and coastal rivers of the state of Pará, in Brazil. Inhabits small shaded streams (Igarapés), ponds, and marginal pools with clear or amber waters, characterized by abundant plant material on the bottom.

Taxonomy and Morphology: Flag Tetra (Hyphessobrycon heterorhabdus). Has the elongated lozenge shape typical of many slender tetras. Often confused with the Penguin Tetra (Thayeria boehlkei) due to the black stripe, but the Flag Tetra has a horizontal, not oblique, posture.

Social Behavior: Peaceful, but active. Tends to be a bit shy if not placed in sufficiently large groups (minimum 8-10 individuals). If the school is sufficient, it swims boldly in open waters creating a striking optical effect.

Coloration and Sexual Dimorphism: "Flag" livery: the flank is horizontally divided by three contiguous and bright stripes (red, gold/white, and very thick black), resembling the Belgian flag. Males are slimmer and have more saturated colors than females.

Aquarium Setup: Minimum 60 cm (24 inches) aquarium, densely planted at the margins with twisted roots to create shelters. The red color of the stripe will stand out superbly under dimmed lights and on a very dark substrate.

Diet and Feeding: Generalist omnivore (micro-predator). Easy diet based on minute flakes and granules. To keep the red line bright, it is essential to regularly provide daphnia, bloodworms, and brine shrimp.

Water Quality: Very hardy if acclimated gradually. Prefers soft and weakly acidic waters, but captive-bred specimens adapt well to neutral waters of medium hardness. Purity (low nitrates) is vital.

Compatibility and Tankmates: Excellent community fish. Peaceful with everyone. Pairs perfectly with dwarf Loricariids, Corydoras, Apistogramma, and other small Characins or Rasboras. Only avoid excessively large or boisterous tankmates.

Aquarium Reproduction: Non-adhesive eggs laid among plants in the morning. A dimly lit breeding tank with a bottom protection grid is recommended to save the eggs from the parents' insatiable appetite.

Risks and Diseases: Hardy species. The greatest danger lies in chronic stress caused by isolation (few specimens) or overly bare tanks, which leads to severe color fading and weakening.