Water care for a Discus: 28 to 30°C, pH 6 to 7
Discus : One of the most demanding species for water quality: very low nitrates, remineralized RO water and 25 to 50 percent weekly changes, even more for juveniles. Any lapse quickly shows in its color and appetite.
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🩺 The health watchpoints on this page are for information only: only a veterinarian can examine your animal and make a diagnosis.
In short: 15 to 20 cm as an adult, 300 L minimum for a group of 5, very soft water between 28 and 30 °C. A gregarious, shy cichlid that forms a group hierarchy and gets outcompeted at feeding time if too harassed. The most demanding for water quality: very soft, acidic, at 28-30 °C, with an RO unit and frequent water changes essential.
The Discus’s water: its real parameters
Temperature of 28 to 30°C, pH of 6 to 7, undetectable nitrites and nitrates under 25 mg/L: that is the contract. A drop-test kit (NO2, NO3, GH, KH, pH) beats any strip — and the nitrogen cycle, three to four weeks before any fish, is non-negotiable.
Water changes and tank upkeep
10 to 20% of the volume weekly, with water pre-heated to tank temperature: thermal shock stresses more than imperfect water, gentle substrate siphoning as you go and filter media rinsed in tank water, never under the tap: chlorine sterilises your filter.
Health: what stalks the Discus
The Discus watch-sheet: hexamita and hole-in-the-head in imperfect water and white spot disease in fragile juveniles. Before any treatment, the reflex is a water test — pouring medicine into loaded water is treating the fever by breaking the thermometer. Well kept, a Discus lives 10 to 15 years.
Frequently asked questions
What water parameters for a Discus?
28 to 30°C, pH 6 to 7, zero nitrites and nitrates under 25 mg/L — checked with drop tests, not by eye.
How often should a Discus tank get water changes?
10 to 20% weekly, water brought to temperature, filter rinsed only in tank water. Consistency beats volume.
The guides that apply to you
- Quarantining a New Fish Before Introduction: Duration and Step-by-Step Protocol
Isolating every new fish for two to four weeks before adding it to the main tank remains the best protection against introducing a disease.
- Filamentous (Hair) Algae in Aquariums: Causes and How to Get Rid of It
Long green strands cling to plants and decor and grow back within days of every cleanup. Understanding why filamentous algae thrives before reaching for a lasting fix.
- Copper and algae treatments: what is deadly for Cherry shrimp
Dwarf shrimp like the Cherry shrimp are far more sensitive to copper than fish. Here is why, and how to avoid an accidental poisoning in a nano tank.
- Introducing Otocinclus Into a Too-Young Tank: The Mistake That Kills Them in Weeks
This small, unassuming cleaner fish is especially sensitive to the ammonia and nitrite spikes of a recently cycled tank.