Temperature requirements vary by species' native habitat. Tropical community (tetras, rasboras, gouramis, platys, corydoras): 76-78°F (24-26°C). Stable temp matters more than exact number. Bettas (Betta splendens): 78-82°F (25.5-28°C). Lower temps suppress metabolism + immune system. Discus: 82-86°F (28-30°C). High temp accelerates metabolism + reduces parasites. Plan tankmates carefully - few species tolerate this range long-term. African cichlids (Lake Malawi, Tanganyika): 76-82°F (24-28°C) depending on lake. Mbuna run cooler than Tanganyikan species. Goldfish (common, comet, fancy): 65-72°F (18-22°C) for fancy. Common + comet tolerate 50-78°F. Cold-water (white clouds, dojo loach, hillstream loach): 65-74°F. Reef tank: 76-80°F (24-27°C). Stable to within 2°F. Above 82°F = oxygen depletion + coral stress. FOWLR: 78-82°F. Slightly higher tolerable than reef. Saltwater fish-only: 76-82°F. Temperature stability: use 2 thermometers (digital + glass) - they cross-validate. Replace heater every 2 years. Use Inkbird controller for redundant safety. Heat waves: in summer, drop tank lid for evaporative cooling, run a fan over surface, freeze water bottles + float (matched temp). Cool back gradually - rapid drop is also stressful.
The full Q&A library answers the most-searched aquarium questions. Browse calculators, glossary, and disease database for related help.
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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