Zoanthids

Zoanthus sp.

Animalia›Cnidaria›Anthozoa›Zoanthidae

📍 Indo-Pacific Reef Systems

Zoanthids (zoas) are colonial soft corals that form mats of individual polyps in an extraordinary range of colours and patterns, making them highly collectible. They are among the hardiest corals for beginner reef keepers and grow rapidly under good conditions. Some zoa morphs contain palytoxin; always wear gloves when handling.

Size2"

Min Tank10g

peaceful

Zoneall

Tank Mates

Ocellaris Clownfish

Small, reef-safe fish that won't disturb zoa colonies and thrive in similar lighting and water parameters

excellent

Cleaner Shrimp

Peaceful invertebrate that benefits the reef ecosystem without harming soft corals

excellent

Pistol Shrimp

Reef-safe and won't predate on or damage zoanthid polyps; may pair with compatible fish

good

Neon Goby

Small, peaceful fish that feeds on parasites and algae without disturbing coral colonies

excellent

Astrea Snail

Herbivorous snail that controls algae growth without damaging zoas or competing for space

excellent

Peppermint Shrimp

Reef-safe scavenger that helps maintain water quality and won't harm established zoa mats

good

Common Diseases

Zoanthid Palytoxin Poisoning (Human)

Symptoms

Skin irritation, respiratory distress, or systemic illness in aquarist after handling; not a disease of the coral itself but a hazard

Treatment

Always wear nitrile gloves when handling zoanthids; wash hands thoroughly after contact. Some morphs contain palytoxin—research specific strains before purchase. No treatment needed for corals; seek medical attention if poisoning is suspected

Brown Jelly Disease

Symptoms

Brown, gelatinous film covering polyps; rapid tissue recession; polyps fail to open

Treatment

Isolate affected colony immediately; perform 25% water change and increase water flow. Remove affected tissue with clean tools if possible. Treat with antibiotics (e.g., erythromycin) or dip in iodine solution. Improve water quality and reduce organic waste

Zoanthid Recession

Symptoms

Polyps fail to open; tissue shrinkage; slow mat expansion; loss of color

Treatment

Check water parameters (pH, alkalinity, calcium, phosphate, nitrate). Increase lighting gradually if PAR is too low. Improve water flow without direct blasting. Reduce feeding of other corals to lower organic waste. Allow 2-4 weeks for recovery before considering the colony lost

Predation by Nudibranchs or Flatworms

Symptoms

Polyps disappearing; visible small organisms on colony; tissue damage

Treatment

Inspect colony closely under magnification. Remove visible predators manually with tweezers. Dip colony in freshwater or iodine solution for 5-10 minutes. Quarantine new corals before adding to main tank to prevent introduction of pests