Coralline Algae (IMAGE) Florida State University Caption Coralline algae have a hard skeleton and are often pink, red, purple, yellow or gray-green. Credit Courtesy of Assistant Professor Sophie McCoy Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.