Banded Dascyllus

Photo: Tim Cameron · © all rights reserved

Chromis damselfish swarm in enormous schools above Porto Palermo's reef, the iridescent blue juveniles concentrated near the surface and adults schooling in darker midwater aggregations of hundreds of individuals. They are planktivores, darting into the water column to seize copepods and retreating to cover at the first sign of a predator — a strategy that makes them a constant and energetic background presence on every dive in the bay. Males defend small patch territories on the reef for spawning, fanning eggs with their fins until hatching and aggressively chasing intruders many times their size.