Green Discus

Geographic Origin and Biotope: Populates the western Amazon (basins of the Rio Japurá, Putumayo, Tefé). Strictly associated with flooded areas where fallen branches form intricate underwater 'galleries'. Navigates slowly among the shadows in weakly flowing waters, escaping predators.

Taxonomy and Morphology: Recognized by recent studies as a separate species from S. aequifasciatus. The shape is the iconic flat disk, almost perfectly circular, highly compressed. Small mouth to graze invertebrates. Can reach 15-18 cm (6-7 inches) in diameter. The undisputed King of the freshwater aquarium.

Social Behavior: Very peaceful and highly gregarious. Isolated Discus get sick from lethal stress. They imperatively require a school of at least 5-6 specimens. In the school, a rigid but quiet hierarchy is established, based on fake frontal charges. They are easily frightened by sudden movements or shadows.

Coloration and Sexual Dimorphism: Extraordinary. Yellow-olive or light brown body base tending to mint green. It is crossed by 9 dark vertical bands (more or less visible depending on mood). The unique feature of the Tarzoo are the dense blood-red spots concentrated in the anal, ventral and caudal area. Turquoise streaks decorate the snout. No visible dimorphism.

Tank Setup: Demands a monumental and tall aquarium (minimum 150 cm x 50-60 cm / 60 x 20-24 inches high, 400 liters / 100 Gal). Ideal biotope: bare fine sand bottom, majestic bogwood roots falling from above to shade (fallen branch style), and Echinodorus (Amazonian plants). Subdued lighting to reduce stress.

Feeding and Diet: Very delicate. Demanding benthic grazers. Often disdain granules if not slowly accustomed. They must eat mashes based on shrimp, mollusks, spirulina (avoid mammalian beef heart in the long run), and mountains of frozen bloodworms and brine shrimp. Multiple modest daily meals spur appetite.

Water Quality: THE CRITICAL PARAMETER. Ultra-sensitive fish to ammonia and nitrates. The water must be feverishly hot (constant 28°C - 32°C / 82-90°F) to avoid lethal intestinal blocks. Weakly acidic or strongly acidic pH (5.0 - 6.5) and very low hardness (GH < 5). Copious and close water changes (up to 30-50% weekly in case of growth).

Compatibility and Cohabitation: Perfect master of docile Amazonian community tanks (Discus Tank). Companions of choice: Cardinal Tetras (often act as reassuring 'dither fish'), large schools of warm Corydoras (e.g., C. sterbai), calm Geophagus and algae-eating Loricariids. NEVER insert nervous cichlids or fast fish that would steal food.

Aquarium Reproduction: One of the most touching parental cares in nature. They spawn on a cone or smooth root. The newly hatched larvae, unable to swim freely, stick to the sides of the parents and feed by grazing for weeks on the hyper-protein epithelial mucus secreted by the father's and mother's skin. Extraordinary to observe.

Risks and Diseases: Prone to Tuberculosis and the infamous Hole in the Head disease (Hexamitiasis) caused by chemical stress and vitamin deficiency. Lethal gill parasites if temperatures drop or hygiene decays.