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title: "Discus Fish: The Complete Expert Care & Breeding Guide" description: "The definitive discus (Symphysodon) care guide: the King of the Aquarium's extreme warm soft-water needs, high-protein diet, breeding and parental slime feeding, and tank mates." slug: discus-fish commonName: Discus Fish scientificName: Symphysodon spp. family: Cichlidae order: Cichliformes difficulty: Expert minTankSize: 55 temperature: "82–88°F (28–31°C)" ph: "5.5–7.0" hardness: "1–8 dGH" lifespan: "10–15 years" maxSize: "8 inches (20 cm)" origin: "South America — Amazon basin" publishedAt: "2026-06-04"

Discus Fish: The Complete Expert Care & Breeding Guide

The discus is the "King of the Aquarium" — a large, round, breathtakingly-coloured cichlid that represents the pinnacle of freshwater fishkeeping. Symphysodon combines stunning beauty with genuinely demanding requirements: very warm, very soft, spotlessly clean water, a rich diet, and a calm environment. Discus are not a beginner fish, but for the dedicated keeper willing to meet their needs, few fish are more rewarding — and their unique parental "slime feeding" of fry is one of the most remarkable behaviours in the hobby.

This guide is the complete reference: discus biology, their extreme water requirements, diet, the warm-water community question, and breeding including slime feeding.

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Species Overview

The discus (Symphysodon spp.) is a large South American cichlid with a distinctive round, laterally-compressed, disc-shaped body reaching about 20 cm (8 inches). Wild forms (green, blue, brown, Heckel) are stunning, and decades of selective breeding have produced an extraordinary array of strains — solid colours, patterns, and "pigeon blood," "snakeskin," and many more. They are widely considered the most beautiful freshwater fish.

Discus are rated expert for clear reasons: they need very warm (82–88°F), very soft, very clean, stable water, a rich varied diet, a large tank, a calm environment (they're shy and stress-prone), and ideally to be kept in a group (they're social shoaling cichlids that pine alone). They're sensitive to water quality, stress, and disease, demanding diligent maintenance. With proper care they live 10–15 years. They're a fish to graduate to after mastering easier species — but the reward is one of the most magnificent display and breeding fish in the hobby.

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Natural History and Origin

Symphysodon inhabits the warm, soft, acidic blackwater and floodplain habitats of the Amazon basin — slow, dark, tannin-stained waters among submerged roots and leaf litter, typically very warm and extremely soft and acidic. This is one of the most specialised habitats of any aquarium fish, and it dictates their demanding care: very warm, very soft, very acidic, very clean water.

Discus are social, shoaling cichlids that live in groups and form pairs to breed, practising the most remarkable parental care in the hobby: newly-hatched fry feed on a nutritious mucus ("slime") secreted on the parents' bodies, grazing it off the adults for their first days of life — a behaviour found in almost no other fish. Their soft, warm, blackwater origins, social nature, and unique breeding biology all define their care. Wild discus are still collected, but most in the trade are tank-bred strains; even so, they retain their demanding environmental needs.

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Water Parameters — Extreme and Exacting

Discus need very warm, very soft, acidic, and pristine water with very low nitrate — the most demanding parameters of any common aquarium fish. The high temperature (82–88°F) and very low nitrate require diligent, frequent water changes (many keepers do large daily or near-daily changes, especially for young/breeding fish). Confirm cycling with the nitrogen cycle tracker, and use the GH/KH converter and water parameters reference to maintain soft, warm, clean conditions. Water quality is the single most important factor in discus health.

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Tank Setup Guide

Tank size

Discus are large, tall, social shoaling cichlids needing a minimum of 55 gallons (210 litres) for a group, with 75+ gallons strongly preferred — a tall tank suits their body, and the large volume buffers the pristine conditions they demand. Keep a group of 5–6+ (lone or paired discus are stressed; a group settles them), unless keeping an established breeding pair.

Aquascape

Discus suit a calm, warm, planted or bare-bottom tank with driftwood and tall plants for security and some open space. Many serious keepers use bare-bottom tanks for easy cleaning (essential given the heavy water-change regime), while display keepers use heat-tolerant plants. Subdued lighting and a quiet location reduce stress in these shy fish. Vertical structure (like for angelfish) suits their tall bodies.

Filtration, flow, environment

Use robust, efficient filtration with gentle flow and, above all, a rigorous water-change routine to keep nitrate very low. A calm, low-traffic environment is important — discus are easily startled and stress leads to illness. Stability and cleanliness are everything.

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Feeding Guide

Discus are carnivore-leaning omnivores needing a rich, varied, high-quality diet.

What to feed

• High-quality discus pellets/granules and flake — formulated staples.
• Frozen and live foods — bloodworm, brine shrimp, daphnia, and the traditional discus "beefheart" mixes (used carefully).
• Live blackworms — relished, excellent for conditioning.
• A varied, rich diet is key to growth, colour, and breeding condition.

How often

Feed several small meals daily (young/growing discus especially need frequent feeding for proper development). Rich feeding plus heavy water changes go hand in hand — the food load demands the cleaning. A healthy discus is round, full-bodied, brightly coloured, and unafraid to feed; a thin, dark, hiding discus signals stress, poor water, or illness.

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Tank Mates and the Warm-Water Community

Discus's very warm water (82–88°F) limits compatible tank mates to fish that tolerate high heat and a calm, soft-water environment. Good tank mates include warm-soft-water fish like cardinal tetras and rummynose tetras (classic discus dither fish, big enough not to be eaten and tolerant of the heat), corydoras species that handle warmth (e.g., sterbai), and other calm, warm-tolerant community fish.

Avoid: cool-water fish (most community species prefer cooler water), aggressive or boisterous fish (which stress shy discus), fin-nippers, and small fish discus might eat. Many keepers keep discus species-only for simplicity and to maintain the pristine conditions and calm the discus need. Use the compatibility checker — and prioritise the discus's warmth, calm, and water-quality needs over a busy community.

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Breeding Guide — Including Slime Feeding

Discus breeding is an advanced, deeply rewarding project, famous for the parental slime feeding of fry. Pairing: raise a group and let a pair form; sexing is difficult outside breeding. A bonded pair cleans a vertical surface (a cone, slate, or broad leaf) and the female lays eggs the male fertilises, both parents fanning and guarding them.

The remarkable part: after the eggs hatch and the fry become free-swimming, they swim to the parents' bodies and graze a nutritious mucus ("slime") the parents secrete on their flanks — the fry's sole food for their first days, with both parents sharing the duty and even signalling the fry between them. This unique adaptation means discus fry are raised on their parents' bodies, an extraordinary sight. As the fry grow, they're weaned onto baby brine shrimp and finely-prepared foods. Breeding demands very soft, warm, pristine water and impeccable conditions; it's the pinnacle achievement of freshwater fishkeeping, and the slime-feeding behaviour is unforgettable to witness.

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Health and Disease

Discus are stress- and water-quality-sensitive, and most health problems trace to poor or unstable water, stress, or imported-fish issues.

Stress-related decline is the biggest risk — discus in cool, unstable, high-nitrate, or busy tanks fade, darken, hide, and stop eating. Internal parasites (hexamita/spironucleus, "hole-in-the-head") are common, especially in stressed or poorly-fed fish, causing weight loss, white stringy faeces, and head lesions — needing treatment (e.g., metronidazole) and pristine conditions. Bacterial and gill infections, ich, and "discus plague" affect stressed or newly-imported fish. Their sensitivity makes quarantine, pristine water, warmth, and a calm environment essential.

Prevention: very warm, very soft, pristine, stable water with low nitrate; rigorous water changes; a varied rich diet; a calm environment; a proper group; and strict quarantine of new arrivals. Discus reward meticulous husbandry and punish neglect — water quality and stability are the foundation of their health.

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Interesting Facts

• The King of the Aquarium. Discus are widely considered the most beautiful and prestigious freshwater fish, the pinnacle of the hobby.
• Parental slime feeding. Discus fry graze a nutritious mucus secreted on their parents' bodies for their first days — a behaviour found in almost no other fish.
• Extreme requirements. Very warm, very soft, very clean water with very low nitrate make discus one of the most demanding common aquarium fish.
• Social cichlids. They're shoaling fish that need a group to feel secure — lone discus are stressed.
• A rainbow of strains. From wild greens and blues to pigeon blood and snakeskin, decades of breeding have produced extraordinary colour varieties.

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Bringing It Together

The discus is the magnificent culmination of freshwater fishkeeping — a stunning, social, large cichlid that demands the most exacting care of any common aquarium fish: very warm (82–88°F), very soft, acidic, pristine water with very low nitrate, maintained by rigorous water changes, in a large, calm tank with a group of its own kind and a rich, varied diet. Meet those demands and you'll keep one of the most beautiful fish on earth for over a decade, very possibly witnessing the extraordinary spectacle of discus fry feeding on their parents' slime. It's an expert fish — graduate to it after mastering easier cichlids like the angelfish, bolivian ram, and german blue ram — but the reward is unmatched. Pair it with warm-water dither fish like cardinal and rummynose tetras, and plan the demanding build with the AI Tank Blueprint generator and the GH/KH converter.