They require very clean water and high light levels for optimal coloration. A distinctive feature is that they are often commensally colonized by Christmas tree worms (Spirobranchus giganteus). Differentiation between Porites and Montipora species is often difficult, and best done on dead specimens, as the skeletal structure of the polyps is important here: Porites usually have better defined corallite walls than Montipora, where these are weaker and often just rather rough. The closely related Bernardpora (formerly Goniopora stutchburyi) are also sometimes confused with Porites, but in principle has larger polyps. Porites are mostly beige to brown in color, rarely green, purple-bluish or striking yellow, and very rarely red specimens are said to occur.