Ruby Zoanthids

Ruby Zoanthids, Zoanthus sp., are colonial zoantharians known for their vivid radial patterning and dense mat-forming growth. This WYSIWYG colony displays bright white to cream centers surrounded by intense ruby-red to crimson radial striping, with darker burgundy outer discs and brown-gold skirts. The strong contrast between the pale centers and saturated red pattern gives the colony its distinctive “Ruby” appearance. Zoanthus polyps are connected by living tissue and can gradually spread across adjacent rockwork under favorable reef conditions. They contain symbiotic photosynthetic dinoflagellates that provide much of their nutritional energy, while the polyps may also capture very fine suspended organic material. Because aquarium color morph names do not reliably correspond to a particular species, Zoanthus sp. is the scientifically appropriate identification.

Care Guide: Zoanthus sp. generally performs well under low to moderate lighting, although established colonies can tolerate moderately strong reef lighting when acclimated gradually. Provide low to moderate, variable water movement that helps keep debris from settling between the polyps without preventing full extension. Place on stable rockwork with enough room for the colony to spread. Maintain stable temperature and salinity along with consistent alkalinity, calcium, magnesium, nitrate, and phosphate. Most nutrition is supplied through photosynthesis, although very fine suspended foods may provide supplemental nutrition. Zoanthids can contain palytoxin or related compounds, so gloves and eye protection are recommended when handling or fragging, and zoanthid-covered rock should never be boiled or exposed to hot water or steam.