They do not tolerate other fish with the same colour or shape. They also provide cleaner services to marine turtles, by removing algal growth from their shells. ДЄs an example of the adaptations made by reef fish, the yellow tang is a herbivore which feeds on benthic turf algae. Resting small fish are still vulnerable to attack by crevice predators, so many fish, such as triggerfish, squeeze into a small hiding place and wedge themselves by erecting their spines. Others cruise the reefs for food in shoals, but return to a known area to hide when they are inactive. Many reef fish confine themselves to one small neighbourhood where every hiding place is known and can be immediately accessed.

Small reef fish get protection from predators by hiding in reef crevices or by shoaling and schooling. Reef fish have also evolved complex adaptive behaviours. Many reef fish have also evolved cryptic coloration to confuse predators. These spines provide formidable defences, and when erected they can usually be locked in place or are venomous.

Most fishes found on coral reefs are ray-finned fishes, known for the characteristic sharp, bony rays and spines in their fins. They have become crowded and complex environments, and the fish have evolved many ingenious ways of surviving. If the triggerfish wants to hide, it will squeeze into a coral crevice and lock itself in place with its spines.Д¬oral reefs are the result of millions of years of coevolution among algae, invertebrates and fish. If the triggerfish attacks, the damselfish will hide in the nearby cauliflower coral. The black and white fish are three-stripe damselfish and the unstriped fish are blue-green chromis damselfish. Orange-lined triggerfish are particularly aggressive. Triggerfish have mouths that crush shells. In the foreground is an orange-lined triggerfish displaying spines.

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