Zoanthids (Zoanthus spp.) – Description & Care
Zoanthids, commonly known as zoas or button polyps, are a diverse and popular genus of soft corals known for their vibrant, multi-colored polyps. They are often found in a variety of hues, including reds, greens, blues, yellows, and even rare color morphs. These corals are prized for their hardy nature and low-maintenance care requirements, making them ideal for beginner and advanced aquarists alike. Zoanthids form colonies of numerous polyps that spread over rocks or substrates, creating a dense carpet of color.
Care Requirements:
1. Lighting
- Low to Moderate (PAR 50-200)
- Zoanthids can thrive under low to moderate lighting, but they also do well with stronger lighting as long as they are acclimated properly.
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Blue spectrum lighting enhances their colors, with actinic lighting bringing out vibrant hues, especially in reds, oranges, and blues.
- Too much light can cause zoas to retract, while insufficient light can lead to poor growth and dull coloration.
2. Flow
- Low to Moderate Flow
- Prefers gentle to moderate flow that allows their polyps to fully extend without being blown around.
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Excessive flow can cause the polyps to retract or get damaged, while too little flow can result in detritus buildup on the colony.
3. Placement
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Mid to lower regions of the tank, where they can receive indirect light and gentle flow.
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Attach to rocks, frag plugs, or substrates in a stable, low-flow area.
- Ensure they have space to grow, as they can spread quickly and compete for space with other corals.
4. Water Parameters
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Temperature: 72-78°F (22-26°C)
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Salinity: 1.023-1.025 SG (35 ppt)
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pH: 8.1-8.4
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Alkalinity: 8-12 dKH
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Calcium: 400-450 ppm
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Magnesium: 1250-1350 ppm
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Nitrates: 5-10 ppm
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Phosphates: 0.01-0.05 ppm
5. Feeding
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Photosynthetic, but can benefit from occasional supplemental feeding.
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Target feed with small meaty foods like mysis shrimp, brine shrimp, or zooplankton.
- Feeding can encourage faster growth and improved coloration, but good lighting is the primary source of energy.
6. Tank Mates & Compatibility
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Peaceful and non-aggressive, Zoanthids are compatible with a wide variety of corals, including other soft corals, LPS, and SPS (though give them enough space to spread).
- Avoid placing them next to aggressive corals (e.g., certain Euphyllia species) that may sting them.
- Safe with most reef-safe fish, but some fish like angelfish may nip at them.
- Zoanthids can also be compatible with invertebrates such as shrimp, crabs, and snails.
7. Special Considerations
- Zoanthids spread easily and can form large colonies, so leave enough space for growth.
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Toxicity warning: Some zoanthid species produce palytoxin, a potent toxin that can cause health issues if ingested or touched without protection (wear gloves when handling them).
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Acclimate to water parameters carefully when introducing them to a new tank.
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Dip before adding to the tank to prevent pests like Aiptasia, nudibranchs, and flatworms.
- Monitor for signs of stress, such as polyp retraction or color fading, which may indicate issues with lighting, water quality, or pests.
Zoanthids are an excellent choice for creating colorful, low-maintenance colonies in your reef tank. They grow well in a wide range of conditions and are highly adaptable, making them a favorite for both beginners and experienced aquarists.
