Blue diamond discus

Symphysodon tarzoo

Also known as Green discus, Tarzoo discus, Symphysodon aequifasciatus tarzoo

FreshwaterFish

Blue diamond discus (Symphysodon tarzoo) — (c) Rmmoura, some rights reserved (CC BY-SA) · cc-by-sa

Care at a glance

Temperature: 81–88°F (27–31°C)
pH: 5.5–7.0
Adult size: 7.9 in (20 cm)
Minimum tank: 65 gal (245 L)
Temperament: Peaceful
Social behavior: Shoaling
Swim level: Middle
Difficulty: Difficult
Breeding: Hard
Rarity: Rare
Origin: Western Amazon basin, Peru, Colombia, and Brazil
Family: Cichlidae

Overview

Discus are tall, slow, peaceful shoaling cichlids that feel safe in numbers, so keep a group of six or more; single fish and pairs tend to be bullied and nervous. They hold in the middle of the water and prefer calm, warm, spotless conditions, which means gentle tankmates that will not outcompete them for food or foul the water. The blue diamond is a solid blue aquarium strain, and it does best in a group of its own kind or with a few quiet dither fish. Feed small amounts several times a day: quality flake and pellets plus frozen bloodworm, brine shrimp, and a good frozen beefheart mix. A tank of around 245 liters or more suits a starter group, paired with large regular water changes.

In the wild

The wild fish behind these strains, Symphysodon tarzoo, lives in the western Amazon basin across Peru, Colombia, and Brazil, in warm, slow backwaters among flooded wood and leaf litter. That water is very warm, soft, and acidic, stained with tannins. Aim for 27 to 31 C and a pH of 5.5 to 7.0, with soft water, tall roots or branches for cover, and pristine filtration since discus are sensitive to waste.

Good to know

Symphysodon tarzoo is the western or green discus, separated from the eastern discus species in 2006 on the basis of body markings and genetics; it is the source of many blue aquarium lines, including the blue diamond. It belongs to the cichlid family and grows to around 20 centimeters. Breeding is hard: a pair spawns on a vertical surface and guards the eggs, but rearing the fry to health demands very warm, immaculate water.

Did you know

For their first weeks, discus fry feed by grazing a nutritious mucus that both parents secrete over their own skin. This contact feeding, sometimes called discus milk, is very rare among fishes and is why the young stay pressed against their parents' flanks.