Rainbow Hornet zoas are a relatively new zoanthid colour morph that has been rapidly increasing in popularity. They have beautiful colouration with a blue centre, surrounded by a thin green ring, a purple face and a brilliant orange skirt. The polyps are of average size and they tend to grow tight to the rockwork. Like all zoas, they are a colonial coral and grow by budding. Under the right water conditions they can grow quite quickly and a single frag can become a beautiful colony in a fairly short period of time.
Zoas are found throughout the world’s tropical and subtropical oceans in a wide variety of habitats. While all the available types of zoas were initially wild collected, the vast majority of zoas available for sale in the hobby today are aquacultured. This helps to ensure colour uniformity and also creates corals that are well adapted to life in an aquarium. In a home tank, zoas are often placed on a rock island to help control their growth, as they have no “off switch”. Many hobbyists will place multiple zoa rocks together in order to create the classic “zoa garden”.
Rainbow Hornet Zoas are tolerant of a wide variety of lighting and flow conditions. However, they should not be placed in areas of extremely high lighting, since this can cause their polyps to remain closed or even to “melt”. Flow should be sufficient to keep the coral clean but not so intense that the polyps remain closed. Generally, zoa rocks placed on the substrate will satisfy both lighting and flow requirements.
Like all zoas, Rainbow Hornet Zoas are photosynthetic and are able to meet their energy needs by using the aquarium lighting. However, they do respond well to spot feeding and can be fed a general coral food such as Reef Roids. Zoas are one of the few corals that prefers more nutrient rich (dirtier) water and may grow faster in tanks with higher nitrate levels.
Due to their speed of growth, fragging zoas is common but it is a bit of an art form. Since they do not have a calcified skeleton that can be cut, polyps must be scraped from the rock and glued to a frag plug or piece of rubble rock. This usually takes a few tries but is fairly easy once mastered. The fragged polyps will soon attach themselves to the plug and begin to grow a new colony. Due to the possibility of the zoas secreting toxins when handled, it is recommended that hobbyists wear gloves and eye protection when fragging zoas.