How Reef Fish Use Sound Underwater

By Rubicon Foundation editorial team

5 min read · 1 November 2026

Fish sounds are part of an underwater sensory world that divers usually cannot hear clearly. Studying how reef fish respond to sounds from predators and other members of their species connects animal behaviour with underwater acoustics—and helps explain how noise, observation and scientific activity may shape what divers encounter.

Why study sound in fish behaviour?

Sound travels efficiently through water, where visual cues can be limited by darkness, turbidity, distance or the structure of a reef. Fish can produce sounds and detect acoustic cues, making hearing relevant to communication, social behaviour and responses to potential threats.

Research on sound production asks what behaviours accompany a sound and what information it may carry. Playback studies add a controlled way to examine responses: researchers present sounds and observe behaviour, comparing responses to different acoustic cues.

What do predator and conspecific sounds mean?

A predator cue may be relevant because it signals danger; a conspecific cue comes from another member of the same species and may be associated with social interaction. These categories frame different questions about how fish detect and respond to their surroundings. The meaning of a sound depends on its context, not simply on its acoustic presence.

Longspine squirrelfish, identified by the scientific name Holocentrus rufus, are the animal focus of this research area. The broader subject is how their behaviour and sound production relate to playback of predator and conspecific sounds—not whether a particular sound always produces one fixed response.

How are playback studies designed?

In a playback experiment, researchers present recorded or otherwise reproduced sound and monitor the animal’s behaviour. The central challenge is separating a response to the sound itself from responses to other features of the experimental setting, such as the presence of equipment or changes in the animal’s surroundings.

Useful observations may include whether sound production occurs and what behaviour accompanies it. Acoustic measurements and behavioural observations answer different parts of the question: one characterises the signal, while the other records what the animal does. Interpretation depends on the sounds selected, the playback conditions and the observations made.

Sound production: the acoustic signals an animal makes.
Playback: a sound presented under controlled conditions to examine a response.
Conspecific: an individual belonging to the same species.
Behavioural context: the actions and conditions surrounding a sound or response.

What does this have to do with diving?

For divers, underwater sound is both a practical feature of the environment and a scientific subject. Boats, tools and other human activities can contribute noise, while a diver’s own movement and equipment can alter the immediate setting. These factors matter when observing animals: behaviour recorded near people may not represent behaviour in an undisturbed setting.

Scientific divers may therefore need to consider how their presence affects the subject being observed, especially in work that depends on natural behaviour or acoustic responses. The relevant question is not simply whether there is noise, but whether its source, timing and context could influence the observation.

How does the subject fit into diving science?

Diving research spans human physiology, medical care, equipment and the behaviour of organisms underwater. Fish acoustics belongs to the broader study of the marine environment encountered by divers, rather than to decompression medicine itself. Its connection to diving science comes through underwater observation, experimental methods and the effects of human activity.

The same careful logic applies across underwater research: define the question, control conditions where possible, and distinguish what was observed from what is inferred. In field work, researchers must also account for the practical limits of working underwater. When you encounter a study of animal sound, check how playback was controlled and how behaviour was recorded.

Frequently asked questions

What is a conspecific sound?

It is a sound associated with an individual of the same species. In playback research, it can be presented as an acoustic cue while researchers observe behaviour.

Why use sound playback?

Playback lets researchers present selected acoustic cues and examine how animals behave in response. The experimental setup and surrounding conditions are important to interpreting those observations.

Can divers affect fish behaviour through noise?

Human activity can add sound and other disturbances to an underwater setting. Whether that affects a particular animal or observation depends on the sound, circumstances and behaviour being studied.

An original research-library explainer written by the Rubicon editors. It is not a summary of a specific publication.