Zoanthid and Palythoa Care Guide: Colourful Soft Corals for Every Reef

No group of corals matches the sheer variety of colours and patterns found in zoanthids and palythoa. From electric orange and neon green to complex multi-coloured morphs with imaginative collector names, these soft corals have built an entire sub-hobby around breeding and trading rare varieties. This zoanthid coral care guide from Gensou Aquascaping at 5 Everton Park, Singapore covers care requirements, placement strategy and the critical safety precaution every zoanthid keeper must know.

Zoanthus vs Palythoa: Key Differences

Zoanthus species tend to be smaller, with individual polyps measuring 5-10 mm across. They typically incorporate sand and debris into their tissue (a characteristic called “incrustation”) and grow in dense, colourful mats. Palythoa polyps are noticeably larger — 15-30 mm across — with a rubbery texture and a connected mat of tissue called coenenchyme. Both genera belong to the order Zoantharia. In hobby terms, smaller “zoas” fetch premium prices for rare colour morphs, while larger “palys” serve as dramatic, fast-spreading ground cover.

Palytoxin Safety Warning

Before discussing care, a critical safety note. Palythoa species — and to a lesser extent some Zoanthus — contain palytoxin, one of the most potent natural toxins known. While the corals are safe to keep in a sealed aquarium, handling them with bare hands, fragging them without gloves and eye protection, or boiling live rock containing palythoa can release the toxin. Symptoms of exposure include chest tightness, difficulty breathing, muscle pain and in severe cases, hospitalisation. Always wear nitrile gloves and safety glasses when handling these corals. Work in a well-ventilated area and never use boiling water to clean rocks with attached zoanthids.

Water Parameters

Zoanthids and palythoa thrive across a wide range of reef conditions, making them genuinely beginner-friendly. Salinity at 1.025, temperature between 25-27 degrees Celsius, alkalinity at 7.0-9.0 dKH, calcium at 380-440 ppm and magnesium at 1280-1400 ppm all work well. They tolerate higher nutrients than SPS corals — nitrates up to 20 ppm and phosphates up to 0.1 ppm rarely cause problems. In fact, ultra-low nutrient systems can actually slow zoanthid growth and dull colours.

Lighting

Moderate lighting suits most zoanthid varieties. PAR values between 80-200 produce good growth and colour expression. Some high-end morphs display their best colours under specific spectrums — experimenting with blue-heavy lighting often reveals hidden fluorescent pigments. Palythoa species handle higher light levels comfortably and can be placed in the upper portions of the tank. Newly purchased zoanthids should be light-acclimated by starting them lower and gradually moving upward over two weeks.

Flow and Placement

Low to moderate flow works best. Excessive current causes polyps to remain closed, defeating the purpose of keeping these corals for their colour display. Position zoanthid colonies on flat rock surfaces or rubble where they can spread naturally. Leave space between different colour morphs unless you want them to grow together — once zoanthid mats merge, separating the varieties becomes very difficult.

Zoanthids spread by extending a mat of tissue across adjacent surfaces, colonising new territory at rates of 1-3 cm per month depending on conditions. They can overgrow neighbouring corals, so monitor aggressive colonies near slower-growing species.

Feeding

Zoanthids obtain most energy through photosynthesis but respond positively to occasional feeding. Broadcast feeding with fine coral foods or phytoplankton once or twice weekly encourages polyp expansion and faster colony growth. Individual polyps in larger Palythoa species accept small meaty foods like mysis or cyclops placed directly on the oral disc.

Common Issues and Pests

Zoanthid-eating nudibranchs (Aeolidiella species) are small, well-camouflaged pests that consume polyps and lay spiral egg masses on the colony’s mat. Dip all new zoanthid frags in coral dip solution for 10 minutes and inspect under magnification. Sundial snails (Heliacus species) are another predator — small, flat-shelled snails that feed exclusively on zoanthid tissue at night. Manual removal combined with repeated dipping controls both pests.

Unexplained polyp closure sometimes results from allelopathic warfare with nearby corals. If a zoanthid colony stops opening, check for contact with aggressive LPS species or chemical warfare from soft corals like leather corals (Sarcophyton).

Building a Zoanthid Collection

Starting a zoanthid garden is one of the most accessible entry points into reef keeping. Common morphs cost $5-$15 SGD per frag on Carousell and Shopee, while rare designer varieties command $50-$200 SGD per polyp. The low care requirements, vibrant colour range and collectible nature of named morphs make zoanthids an endlessly engaging part of the hobby. Just remember the safety precautions — respect the toxin, wear your gloves, and enjoy the colour.

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