Madracis and Cladocora are two of the small sized coral species that do occur in this part of the Mediterranean. They are actual residents of the Med and like most coral very slow growing. So they main reason to keep a close eye on them is to be able to observe the population of something that takes a long time to establish and/or change.
Mandrakis (upper picture) is generally found in dark shadow walls and overhangs, little caves etc. Cladocora can also be found as a miniature reef (up to about 15cm in diameter) inside the seagrass meadow or other shaded areas.