These appear to be Lobophyllia valenciennesii. Most were photographed on southern Kwajalein Atoll lagoon pinnacles but some on the seaward reef.
Like Lobophyllia robusta and others, this species can sometimes show red color at depths below that which red light from the sun penetrates.
The photo below was taken with available light using a video camera at a depth of greater than 30m on a sunken WWII wreck.
The next two photos show a colony taken with artificial light and (at a later time) with natural light with a color correcting filter.
Created 23 April 2020
Updated 9 June 2023