Discus

Overview

The Discus (Symphysodon species), nicknamed the "king of the aquarium", is a disc-shaped, brilliantly coloured cichlid considered one of the most beautiful freshwater fish. Discus are also one of the most challenging: requiring very soft, very warm, immaculately clean water and large groups for proper behaviour.

Natural History

Native to the Amazon basin in slow-moving blackwater rivers. Three species (S. aequifasciatus, S. discus, S. tarzoo) plus many captive-bred strains.

Appearance

Adults 15-20 cm body length, disc-shaped. Brilliant patterns and colours: red turquoise, blue diamond, pigeon blood, snake skin, leopard, marlboro, and dozens more.

Temperament & Tankmates

Peaceful cichlids. Best in groups of 6+ - solo Discus are stressed and short-lived. Pairs and trios often produce dominance issues; large groups are most stable.

Tankmates: only fish that tolerate the high temperatures and soft water Discus require. Cardinal Tetras (often), Sterbai Corydoras, peaceful South American fish.

Tank Size & Setup

Minimum: 200 L (55 gallon) for a group of 4-6. Tall tank preferred.

Heavy filtration, very clean water, large weekly water changes (50%+).

Water Parameters

• Temperature: 28-30°C (warmer than typical tropical).
• pH: 5.5-7.0.
• Very soft water.

Diet

Carnivore. Frozen bloodworms, brine shrimp, beefheart (controversial), quality Discus pellets, blackworms. Feed 2-3 times daily; juveniles more often.

Health & Lifespan

10-15 years.

Common concerns:

• Sensitive to water quality - Discus are the fish that demand "perfect" water.
• Internal parasites.
• Hexamita.
• Bacterial infections.

Pros & Cons

Pros: stunning appearance, intelligent, long-lived, social. Cons: demanding water quality, expensive setup, sensitive to disease, not for beginners.