Quarantine & Buying

7 signs: clear eyes with no cloudiness, vivid colors without paleness, fully spread fins, a round (not thin) body, calm breathing, eats actively when fed, doesn't rub against the décor.

Minimum 5–6 fish of the same size, ideally from the same batch. 1–2 discus → stress + lethal bullying. Buy them all at once, don't add them later one by one.

The drip method, 45–60 minutes: float the bag in the aquarium for 15 min to equalize temperature, then slowly drip aquarium water into the bag until you triple the volume. Transfer the fish with a net — do NOT pour the bag water into the aquarium.

Mandatory if you already have fish in the aquarium — 2–4 weeks in a separate 60–100L aquarium for observation. Optional if it's your first discus aquarium and they all arrive together from the same source.

Refusing food for 1–3 days, visible stress bars, sitting in a corner, pale colors. NORMAL. Abnormal = rapid breathing, swimming sideways, refusing food for over 5 days, visible lesions.

Minimum 4 weeks: week 1 — observation, week 2 — dual treatment Praziquantel + Metronidazole, week 3 — recovery, week 4 — check. For freshly imported Asians: 6–8 weeks. Below 4 weeks you miss the parasite cycles (Hexamita 14–28 days asymptomatic).

Beginners: Stendker (hard European water, health, 150–450 RON/piece) or a verified local breeder (identical water). Advanced: Asians through an EU importer or premium local breeders. Breeding: locals or Asians (Stendker are difficult to breed as a hobbyist).

DOUBLE polyethylene bags with a 1/3 water + 2/3 pure oxygen ratio, a 3cm polystyrene insulated box, a constant temperature of 28–30°C (heat pack in winter, cold gel in summer), total darkness. Stop feeding 24h before. Maximum 1 discus/bag for transport over 4h.

Yes, but through a slow 6-week transition: steps of at most +25 ppm TDS/week and +0.2 pH/week. You start at TDS 130–150 ppm (Asia water) and reach your water (250–400 ppm). A sudden transition = lethal osmotic shock, 40–80% mortality. You need an RO unit + remineralizer (Sera Mineral Salt).

Ask for 6 mandatory photo angles (left/right side, front, dorsal, ventral, head close-up) + 3 minutes of video (LIVE feeding, mid-water swimming, breathing close-up). 12 questions for the seller about water parameters, age, quarantine, DOA guarantee. For purchases >500 RON insist on a LIVE video call.

Refusing food on LIVE video (the definitive test) · white stringy feces (Hexamita) · breathing over 120/min · permanently intense stress bars · visible lesions (ulcers, HITH, dropsy) · the seller refuses LIVE video or doesn't know the parameters exactly · price 40%+ below market.

Not for a first aquarium. Discus require a high temperature (29–30°C), stable parameters and frequent water changes. Recommended after at least 6–12 months of experience with tropical fish.

As a Romania estimate (2026), roughly €30–60/month (150–300 RON) for 6 discus in 250L: electricity (~€12–20), food (~€8–16), dechlorinator + tests (~€4–8), water changes (free if you have tap water). Costs vary a lot by country — see our calculator for an estimate based on your own tariffs.

As a Romania estimate (2026), a complete setup for 6 discus runs roughly €500–1100 (2500–5500 RON): a 250L aquarium (~€200), an external filter (~€100–160), heaters (~€40), tests + accessories (~€60), plus 6 discus at ~€20–30 each (~€120–180). Prices vary widely by country and supplier.

An aquarium cycled for 4–6 weeks, stable parameters (ammonia + nitrite = 0), a temperature of 29–30°C, a working filter, dechlorinator, and a quarantine spot if you already have fish.

Top 5 killers: an uncycled aquarium (70%), temperature below 28°C (50%), an undersized filter (40%), cheap sick fish (60%), preventive treatments without a diagnosis (30%).

The first year: discus ONLY. After 1 year, options: Corydoras sterbai, cardinal tetra (careful — they can be eaten). NEVER: angelfish (parasites), barbs (nip), guppies (different requirements).

NO. Treatments with no symptom = they destroy the filter's bacterial colony → ammonia crisis. Treat only based on confirmed symptoms. At the first sign: test the water (90% of 'diseases' are bad parameters).

Common invisible causes: ammonia below 0.25 ppm (undetectable with strips), temperature dropping at night, old oxidized food, a bad source (fish already sick at purchase).