Soft coral (zoanthids, mushrooms, leathers, GSP, Xenia) is ideal for nano reefs under 30 gallons. They tolerate the parameter swings small tanks experience, color up under modest light, and propagate easily. Add hardy LPS (Trachyphyllia, candy cane, hammer) once the tank stabilizes. Avoid SPS in nano reefs under 20 gallons.
Nano reef tanks (under 30 gallons) have a fundamental constraint: small water volume swings parameters faster than large tanks. A 5-degree temperature spike in a 200-gallon tank takes hours; in a 10-gallon nano it takes 20 minutes. Coral selection has to account for this volatility.
The right coral for a nano: parameter-tolerant softies and hardy LPS. The wrong coral: demanding SPS that won't survive the inevitable parameter swings.
Yes, but only one or two specimens of the most forgiving species (montipora capricornis, montipora digitata). Even these will struggle in tanks under 20 gallons.
In most US regions yes, especially apartments without strong AC. Nano-tank evaporation rates are high relative to volume, and water temp can spike 5-8°F on hot days. A small chiller ($150-300) protects the investment.
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.
Saltwater livestock · Freshwater livestock · Coral catalog · Care library · Q&A library (222) · Glossary (127) · Disease database (50) · Calculators (29) · Interactive tools (7) · Husbandry deep-dives · DIY projects · State legality directory