Green Terror

The Green Terror (Andinoacara rivulatus) is native to the river systems draining into the Pacific coast of Ecuador and Peru, inhabiting clear to turbid rivers, estuaries, and coastal lagoons. It is one of the most visually impressive cichlids available in the hobby, with males developing a pronounced nuchal hump and displaying iridescent turquoise-green scales edged in metallic blue, overlaid on a base of olive-green or teal.

Two colour forms are recognised: the 'gold saum' variety, which displays an orange-gold margin on the caudal and dorsal fins, and the 'white saum' variety, with a white or silver fin margin. Both forms are widely available and are equally aggressive and demanding in terms of care.

Males grow significantly larger than females, reaching up to 30 cm, while females typically stay under 20 cm. As they mature, males develop the characteristic cranial hump that adds to their imposing appearance. In the aquarium, Green Terrors are robust, active swimmers that occupy all levels of the water column.

Green Terrors are highly territorial and will attack and kill smaller or less aggressive fish. They are best kept alone, in a bonded pair in a large tank, or alongside equally aggressive large cichlids. Breeding pairs require careful monitoring as males can become dangerously aggressive toward females, and the tank should provide visual barriers to allow escape.

Tank Setup A minimum 200-liter aquarium is needed for a single Green Terror, with at least 350 liters for a pair. Use a sandy or fine gravel substrate, large smooth rocks for territory demarcation, driftwood, and extremely robust or artificial plants. All décor must be stable as Green Terrors will rearrange it constantly. Strong filtration with high turnover is essential.

Water Parameters Maintain temperature 20–26°C, pH 6.5–8.0. Green Terrors are adaptable to a wider pH range than many cichlids. Perform 25–30% weekly water changes. Water hardness should be moderate. A powerful canister filter is recommended; supplemental powerheads can help with circulation.

Feeding Green Terrors are carnivores that accept a variety of meaty foods. Offer large cichlid pellets, frozen krill, mysis shrimp, earthworms, and occasional live foods. Feed once or twice daily. Carotenoid-rich foods help enhance the iridescent blue-green coloration and orange fin margins.

Tankmates Extremely limited options due to aggression. Compatible tankmates must be of similar size and aggression level: Oscars, Jack Dempseys, and large Plecos are the safest choices. Any smaller fish will be harassed or killed. A mated pair requires a very large tank with visual barriers to prevent the male from injuring the female outside of spawning periods.

Breeding Green Terrors are open spawners. The female deposits eggs on a flat stone or cleaned substrate area, and both parents guard aggressively. Eggs hatch in 2–3 days; fry become free-swimming within a week. The male's aggression peaks during breeding and careful monitoring is needed to protect the female.