[Chris5]

This is one for the GSP keepers ... since the introduction of a my small GSP 3 mos ago it has quadrupled in size and even molted onto adjoining rocks ... all good stuff ...

The past 2 days though (granted I have been moving some other corals around for placement issues) is has for no apparent reason retracted almost 100% randomly during the course of the day ... it leaves about a 1/3 inch out polyp wise for awhile than later on fully extends back ... today is the second day i noticed it ...

This is not a water issue since all other corals (lps, softies, zoos etc..) are fine, open and healthy ...

The GSP is next to some yellow polyps creeping towards it, and a green toadstool ... could it be a hitchhiker disturbing it?

	LPS Large Polyped Stony corals – In the aquarium hobby this is a common division of the species of stony corals based upon the visual assessment of the size of the polyps. Corals in this category were among the first stony corals to be kept successfully in captivity and include many very beautiful species. Commonly kept Genera include Euphyllia (hammer/frogspawn coral), Favia (brain coral), Plerogyra (bubble coral), Lobophyllia (meat/tooth coral), and Caulastrea (candycane coral). LPS corals also include the popular solitary non-colonial stony corals such as Fungia (plate coral), Cynarina (button coral), Trachyphyllia (open brain coral), and Herpolitha (tongue coral). Like their SPS counterparts, LPS corals require good water quality, intense lighting of the appropriate spectrum, adequate water movement and regular supplementation of calcium.