What's the best coral for a nano reef?

Short answer

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.

In depth

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.

Best nano reef coral by category

• Soft coral foundation: zoanthids ($15-50), mushrooms ($10-40 each), toadstool leather ($25-60), green star polyps ($15-30), pulse Xenia ($20-40). Cover the bottom and middle.
• Hardy LPS: Trachyphyllia (open brain) on the sand bed ($30-80), candy cane / Caulastrea ($25-50), hammer or torch coral / Euphyllia ($30-100), acanthastrea / acan ($30-100 per polyp). Tolerant of nano-tank parameter swings.
• Avoid in nano: most acropora, demanding goniopora, large euphyllia colonies, demanding chalices, anemones (BTA can work in 20+ gal but adds risk).

More questions

Can I keep SPS in a 30-gallon tank?

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.

Do nano reefs need a chiller?

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.