Why zoas are a great coral to start with
Zoanthids (zoas for short) are small colonial polyps that come in just about every color you can imagine, and plenty you can't. They grow fast, they forgive small mistakes, and a single frag can turn into a whole garden over time. Their close cousins, palythoas (palys), have bigger polyps and similar care.
Lighting: less is more
Zoas do best under low to moderate light, roughly 50 to 150 PAR if you own a PAR meter. If you don't, think "lower half of the tank" to start.
- Too much light: polyps stay closed or shrink, or their colors wash out.
- Too little light: long, stretchy stalks reaching for the light, like a teenager reaching for the fridge.
Start new frags low, then move them up a few inches every week or so if they look happy and open.
Flow: a gentle sway
Aim for moderate, indirect flow. The polyps should sway, not get blasted flat. Good flow keeps waste and detritus from settling on the colony, which helps prevent problems.
Water parameters
Stable beats perfect. These are common targets for a zoa and softie tank:
- Temperature: 76 to 80°F
- Salinity: 1.025 to 1.026 specific gravity (about 35 ppt)
- pH: 8.0 to 8.3
- Alkalinity: 7 to 11 dKH
- Calcium: 400 to 450 ppm
- Magnesium: 1,250 to 1,400 ppm
- Nitrate: about 2 to 10 ppm
- Phosphate: about 0.03 to 0.10 ppm
Here's the twist: zoas like a little nitrate and phosphate. A tank that tests at zero for both can leave zoas pale and slow. Don't chase zero.
Feeding
Zoas get most of what they need from light, but many keepers see better growth with occasional target feeding: a small amount of fine coral food once or twice a week. Turn the pumps off for a few minutes, feed gently, and don't overdo it. Leftover food just becomes nitrate and algae.
Common zoa pests
A good coral dip and a close look at every new frag will stop most problems before they start. Watch for:
- Zoa-eating nudibranchs: tiny, well-camouflaged slugs that blend right in with the polyps.
- Sundial snails: small, flat, spiral-patterned snails that hide at the base of colonies.
- Sea spiders: small, leggy critters that pick at polyps.
If a colony that was doing fine suddenly stays closed, look closely (a flashlight helps) before blaming your parameters.
Safety: wear gloves
Some zoas and palys contain palytoxin, a very strong toxin. When handling, cutting, or scrubbing them, wear gloves and eye protection, and wash up afterward. Never boil, microwave, or pressure-wash rock with zoas or palys on it. If you feel unwell after handling corals, see a doctor and mention palytoxin.
Quick checklist
- Low to moderate light, and move up slowly
- Gentle, indirect flow
- Stable parameters, with a little nitrate and phosphate
- Dip and inspect every new frag
- Gloves on, always
Ready to start (or grow) your zoa garden? Our Classics are a great first pick, and our Collector Frags are for when the addiction fully sets in.