Introduction

Zoanthids and Palythoas, collectively known as Zoas & Palys, are some of the most popular corals in the reef-keeping hobby. Known for their vibrant coloration, rapid growth, and wide availability, and endless variety, these colonial polyps are a staple in both beginner and advanced reef tanks. However, while they are hardy and visually stunning, they also require special handling due to the potential presence of palytoxin, one of the most dangerous natural toxins.

Scientific Name & Identification

Both Zoanthids and Palythoas belong to the order Zoantharia. Zoanthids usually display smaller, tighter polyps that form dense mats, while Palythoas have larger, fleshier polyps that may grow in thicker colonies. Their wide variety of morphs and color patterns—ranging from neon greens and oranges to rainbow mixes—makes them a centerpiece in reef aquariums.

⚠️ Palytoxin Safety: Palythoa species, in particular, are known to produce palytoxin. This compound is dangerous if it comes into contact with cuts, eyes, or is inhaled as aerosol during fragging with hot water. Reef keepers should always wear gloves, eye protection, and handle colonies with extreme care.

Natural Habitat

In the wild, Zoas & Palys thrive across shallow reefs, lagoons, and rubble zones in the Indo-Pacific, Caribbean, and other tropical oceans. They form dense colonies that carpet rocky areas, often outcompeting other corals in their environment. Their adaptability allows them to handle a wide range of aquarium conditions.

Aquarium Care & Setup

Zoas & Palys are relatively forgiving and thrive under stable reef parameters:

• Temperature: 74–80°F (23–27°C)

• pH: 8.1–8.4

• Salinity: 1.024–1.026

• Flow: Moderate, to prevent detritus buildup

• Lighting: Moderate (50–150 PAR), with coloration varying depending on spectrum and intensity

They can be placed on rockwork or frag racks, where they spread rapidly. Many aquarists design “zoa gardens” featuring multiple morphs grown side by side for a colorful display.

Feeding Zoanthids & Palythoas

While primarily photosynthetic, Zoas & Palys may accept supplemental feeding, though they don't have a very strong feeding response. Fine particulate foods such as reef roids, phytoplankton, and powdered coral blends can encourage faster growth and more vibrant colors. Feeding 1–2 times weekly is often sufficient.

Growth and Behavior

Zoas & Palys multiply through budding, and under the right conditions can grow into large mats that cover rockwork. This makes them semi-aggressive, as they may crowd or overtake neighboring corals if not managed. Regular fragging helps keep colonies contained and allows aquarists to share or sell new frags.

Tankmates

These corals are well-suited for mixed reefs, pairing well with peaceful fish, invertebrates, and other corals. Avoid housing them near particularly aggressive corals that may outcompete or sting them.