Royal blue tangs have a "battle royale" on the reef

The royal blue tang, also known as the regal blue tang is a gorgeous fish, but it's fascinating for reasons that go far beyond the beautiful colour. This fish start out as eggs, which is not unusual, but they hatch 24 hours after fertilization and begin their life in the ocean as larvae that feed on plankton.

As a fish species, they are important, but not as human food. Since they eat algae that has bacteria, they can cause ciguatera poisoning if consumed. They are important as bait fish for other species, contributing to the fisheries industry and overall health of the reef.

Tangs have a caudal spine that can inflict a serious wound. The spines protrude when the tang experiences stress. With a quick, sideways thrashing motion, the spines are used as a weapon. The injuries caused are prone to infection. Some tangs are believed to also be venomous.

These two fish are involved in a territorial dispute or a courtship attempt. It's difficult to tell the two situations apart. The fish dart rapidly up and down and in circles as one pursues the other. Scuba divers are delighted to find these fish on the reef. They are very photogenic and visually appealing. The royal blue colour that lends them their name is extremely striking.