This is a macro image of a few square inches of reef-- so small that many details went unnoticed until I inspected the developed image weeks later.  Three tiny crabs share space on a beautiful blue tunicate with golden-ringed siphons, while a fully extended fan worm feeds from the passing current. The blue tunicate (more commonly known as a "sea squirt") is only about one  inch tall.  At the slightest touch the sensitive fan worm is capable of retracting into its tube, quicker than the blink of an eye. A colony of greenish-brown and white tunicates occupy the foreground. These tunicates, a type of Urn Ascidian,  get their green color from symbiotic algae living within their perforated, hollow structure. Sea squirts are often confused with sponges, but contract when touched-- sponges lack a nerve cord and therefore don't react. Identification: blue tunicate (or "sea squirt"): Rhopalaea sp. green tunicate (or "sea squirt"): Atriolum robustum Sabellid ("fan") worm: Sabellastarte indica crabs: unknown back to Gallery II