The faeces of coral-eating fish may act as “probiotics” for reefs, according to a study.

Previously it was thought that corallivore – fish such as pufferfish, parrotfish and butterfly fish that eat coral – weakened marine surfaces. But new research suggests that by eating some parts of the coral and then pooing in different areas of the reef, they are part of a cycle that redistributes beneficial microbes that can help coral thrive.