Zoanthids (Zoanthus / Palythoa spp.)
The Zoanthids (Zoanthus / Palythoa spp.) is a reef aquarium staple kept for colour, motion, and aquascape structure. This profile matches our other coral and invertebrate guides with origin, lighting, flow, water chemistry, feeding, placement, and husbandry pitfalls.
Keeper notes: Some Palythoa produce palytoxin — never scrub dry rock uncovered; wear gloves and rinse tools. Place away from aggressive LPS sweepers.
Natural Habitat and Origin
Wild colonies are associated with tropical Indo-Pacific and Atlantic reef flats and rock walls. Translating that into aquariums means mature rock, stable salinity, and lighting/flow that match the species’ depth preference rather than blasting every coral with identical PAR.
Appearance and Colony Form
Typical aquarium size/range: colonies spread across rock; individual polyps a few mm to ~1 cm. Healthy tissue looks inflated, colourful (or naturally brown with strong fluorescence under actinics), and responsive to light cycle changes. Receding tissue, bleach, or stringy pests deserve immediate chemistry and pest checks.
Lighting and Flow
- Light: low to medium (species-dependent; watch for bleaching or browning)
- Flow: low to moderate chaotic flow
- Acclimate new frags by starting lower and raising intensity over 1–2 weeks
- Observe for closed polyps (too much flow/light) or stretched searching behaviour (too little)
Water Conditions
- Temperature: 75–80°F (24–27°C)
- Salinity / SG: 1.024–1.026
- pH: 8.1–8.4
- Tank: nano reef to large mixed reef; mature systems preferred
- Alkalinity / calcium / magnesium: keep reef parameters stable; avoid big daily Alk swings
Feeding
Ecology: photosynthetic (zooxanthellae) plus occasional phytoplankton / coral foods. Many photosynthetic corals still benefit from periodic target feeding or broadcast reef foods when nutrient export is strong. Feed lightly — excess nutrients fuel algae.
Placement and Aggression
Give chemical and physical space. LPS sweepers, zoanthid mats, and anemones can wage slow wars across rock. Mount frags on plugs for easy rearranging while they find a permanent home.
Ease of Care
Care level: beginner (handling toxins with caution). Stability, cleanliness, and patience outperform constant additive tinkering.
Common Problems
- Bleaching from sudden light intensity changes
- Tissue recession from Alk crashes or pests
- Chemical warfare when coral aggression is ignored
- RTN/STN events after shipping stress or parameter spikes
Related Reading
Conclusion
Zoanthids (Zoanthus / Palythoa spp.) can be a showpiece coral when lighting, flow, and water chemistry stay consistent. Use this guide alongside our other invertebrate and reef profiles for clear, practical long-term care.
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