Green terror

Geographic Origin and Biotope: Endemic to the Pacific slope of South America (Ecuador and Peru). Thrives in rivers, coastal streams and hill lakes, tolerating significantly lower water temperatures (20-24°C / 68-75°F) compared to Amazon basin Cichlids.

Taxonomy and Morphology: Popularly known as the "Green Terror", recently renamed Andinoacara rivulatus. Reaches titanic proportions for the genus: up to 30 cm (12 inches) for males, 20 cm (8 inches) for females. Develops an extremely stocky, powerful build with a snub snout.

Social Behavior: The nickname "Green Terror" accurately reflects the bellicose and domineering nature of mature males, who dominate the tank by terrorizing and subduing anyone who crosses their path. They must be managed as extreme territorial predators.

Coloration and Sexual Dimorphism: Visually breathtaking. Brilliant emerald or olive green body covered with a fluorescent turquoise scaly reticulated pattern. The edges of the dorsal and caudal fins are marked by a thick and flashy orange or white band. Adult males show off a pronounced nuchal hump (lipid bump on the forehead) and very pointed fins.

Aquarium Setup: The aggressiveness and size demand huge tanks: minimum 300 liters (80 gallons) for a single pair. The setup requires huge boulders anchored to the bottom, gravel to dig and large roots. Plants will be inexorably uprooted or torn during patrolling or reproduction.

Diet and Feeding: Omnivorous but strongly carnivorous (piscivore/macro-invertebrates). Needs a robust protein intake: maxi size feeds for carnivorous Cichlids, slices of raw fish (cod/silversides), whole frozen shrimp, giant earthworms. Offer peas or spirulina to aid digestion.

Water Quality: Extremely robust and chemically tolerant (pH 6.5-8.0, GH 4-15), BUT strictly requires cool temperatures (do not exceed 24-25°C / 75-77°F). Like all voracious eaters, it pollutes heavily: oversized external filtration is vital.

Compatibility and Tankmates: Strictly NOT recommended in standard community tanks. Cohabits exclusively with gigantic and equally aggressive Central or South American Cichlids (Jaguar Cichlid, Jack Dempsey, large Oscars) and titanic armored plecostomus in tanks over 600 liters (150 gallons).

Aquarium Reproduction: Hyper-prolific if the pair is formed. They lay up to 400 eggs on previously cleaned flat rocks. Parental ferocity is frightening: a breeding male in a tight tank will beat to death or claim the space of the entire aquarium, forcing other fish into a corner.

Risks and Diseases: The main cause of disposal by aquarists is not disease (they are very resistant) but the murder of tankmates. Sensitive to poor water qualities, which manifest with Hexamita (hole in the head) and fungal infections on frayed fins.