Disease prevention beats treatment - here's the protocol that works. 1. Quarantine every new fish 30 days minimum. Use a separate 20-gallon tank with mature sponge filter. Treat prophylactically: SW = 14 days copper + 2x prazi at days 1+14. FW = prazi + general cure 7 days. Observation only after that. 2. Maintain stable water parameters. Test ammonia + nitrite + nitrate weekly. Reef = also alk/Ca/Mg/PO4. Match temperature within 2°F across water changes. Sudden parameter swings stress fish + invite disease. 3. Varied high-quality diet. 2-3 different foods rotating: high-quality pellet (NLS, Hikari, Fluval Bug Bites), frozen mysis or bloodworms 2-3x weekly, occasional live brine. Add garlic supplement (Selcon, Vita-Chem) for marine. Strong nutrition = strong immunity. 4. Avoid overstocking. Use AqAdvisor or our stocking calculator. Overcrowded fish stress + immunocompromise. 5. Minimize stress. No aggressive tankmates (research compatibility). No bright lights all day - need dim/dark periods. Use soft nets or barehand transfer. Avoid bumping the tank or sudden movements. Match destination water before transferring. 6. Disinfect everything between tanks. Nets, gravel vacuums, buckets - dedicated per tank or 10% bleach soak + rinse 3x. Cross-contamination spreads disease. 7. UV sterilizer. 9-13W UV catches free-swimming parasites + bacteria. Optional but reduces ich/velvet outbreaks dramatically.
The full Q&A library, calculators, diseases, glossary, and interactive tools answer the most-searched aquarium questions.
Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.
Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.
Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.
Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.
Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.
How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.
What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.
How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.
Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.
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