Ferocious, territorial, extremely pugnacious, and fortunately only four inches long. In the background is the tentacle of a Giant Anemone Condylactus gigantea .
Unfortunately, the shot is clouded by condensation on the camera lens. The blue spots are incredibly intense, like LEDs. Lettuce Coral at upper-left, Common Brain Coral Diploria strigosa at lower-left.
Red algae actually vary in color from straw-yellow to deep-purple or black in appearance.
Agardh's Red Weed - Agardhiella subulata is very common and grows in tufts and clumps to about 12" in sunny shallow areas.
Laver or Porphyra ( above ) is similar to Ulva in many ways, although unrelated. It grows interspersed with Ulva in shallow sunny areas, and like Ulva, it is edible.