Question 1

Why won't my discus eat?

Accepted Answer

In the first 3–5 days after bringing them home it's normal — transport stress. Beyond 5 days = a problem: check the temperature (29–30°C / 84–86°F?), ammonia/nitrite (must be 0), bullying in the group, or internal parasites (Hexamita). See the Discus not eating guide.

Question 2

Why are my discus dark and hiding in a corner?

Accepted Answer

The most common causes: poor water parameters (test ammonia + nitrite immediately), temperature below 28°C (82°F), stress from bright lights or aggressive fish, or disease. Dark stress bars lasting over 48h with no visible cause = a warning sign. Details in our discus body language guide.

Question 3

How often should I change the water for discus?

Accepted Answer

2–3 partial water changes per week, 25–30% each, with dechlorinated water at tank temperature (±1°C). For fry: 50% daily. Discus are extremely sensitive to accumulated nitrate — frequent water changes are mandatory, not optional. See water changes step by step.

Question 4

What temperature should the water be, and why not 26°C?

Accepted Answer

It must be 29–30°C (84–86°F). Below 28°C (82°F) the immune system collapses and Hexamita (internal parasites) + Ich (white spot) appear within 1–2 weeks. High temperature isn't a preference — it's the definition of the species. See the ideal temperature for discus.

Question 5

How many discus can I keep together, and in what tank?

Accepted Answer

A minimum of 5–6 discus of the same size, in at least 200L (55 gal), 250–300L (65–80 gal) recommended. Below 4 fish, aggressive hierarchies and lethal bullying appear. Buy them all at once from the same source, don't add them one by one. See tank size.

Question 6

Why do my discus die even though 'I did everything right'?

Accepted Answer

Top invisible causes: an uncycled tank (ammonia poisoning), temperature dropping at night, preventive treatments without symptoms (they destroy the biofilter), sick fish at purchase. 90% of 'diseases' are actually bad parameters. See common beginner mistakes.

Question 7

Can I keep discus with other tropical fish?

Accepted Answer

The first year: discus ONLY. After 1 year of experience: Corydoras sterbai, cardinal tetra, rummynose tetra (tolerant of 29°C). NEVER angelfish (transmit parasites), barbs (nip fins), guppy/molly (different water needs). See the best tank mates.

Question 8

Is tap water good for discus?

Accepted Answer

Yes, in 90% of cases. Dechlorinate with Seachem Prime or Tetra AquaSafe and let it reach tank temperature. Only if your TDS is above 400 or pH is very alkaline (8+) do you need reverse osmosis. pH stability matters more than the exact value. See water parameters for beginners.

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Did you know the discus is often called the "king of the freshwater aquarium"?

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