These WYSIWYG Red Zoanthids are very popular sellers. While these and most soft corals do not absorb a significant quantity of carbonates (they do not quickly lower your tank's Alkalinity as they grow), they do appear to appreciate Alkalinity maintained at 7.5dKH or higher. If the Alkalinity starts to drop below 7dKH, their growth slows and they do not appear as open, colorful, and “happy”. To see more images of this variety of coral check out the Stock version of Red Zoanthid coral here. Like all the corals listed from TerraReef, this specimen is an aquacultured coral protected by our strict 90+ day quarantine protocols. It is very important that you are aware of the care requirements of these corals before ordering. Please take some time to read some information from a few sources. This item is a WYSIWYG item meaning the specimen you receive will be the exact one in the picture. Sometimes we include images of our mother colonies as well to give an idea of what the corals will grow into under proper care. Size is an approximation.