Fish Make Angry Noises When They Feel Threatened

Story at-a-glance -

  • A fish called the French grunt produces a “grunting” sound when it feels threatened
  • The noise is produced through repeated grinding of its teeth
  • Fish communicate with a variety of noises such as booms, growls, thumps, whistles, and musical notes
  • Fish sounds are produced by vibrations, grating teeth, blowing bubbles, rattling their bones, clacking their jaws, and more

By Dr. Becker

Many are surprised to learn that fish make noises, but they do – and that’s just one way they communicate. A fish called the French grunt, for instance, is well-known to vocalize but it has no voicebox, leading researchers to wonder where the noises were coming from.

They noticed enamel on the fish’s teeth had actually worn away, and it turns out this is due to repeated grinding of its teeth.1 This movement is what produces the “grunting” sound, and the fish make the call when they feel threatened. You can hear it for yourself in the video above.

The sound production, which is thought to be a relatively new phenomenon in the fish, is likely an adaptation of the food-processing mechanism. The grinding movement involves the pharyngeal jaws, a second set of jaws that is typically used for manipulating and swallowing prey.2

What Do Fish ‘Talk’ About?

If you were able to tune in to the sounds beneath the surface of the ocean, you’d hear a veritable symphony. An estimated 500 species of fish “talk” by making a wide array of noises.

Some use their swim bladder, which is a muscle primarily used for going up and down to and from the water’s surface, to make sound-evoking vibrations. Such noises include booms, growls, thumps, whistles, and musical notes. Other fish, like the French grunt, grate their teeth to make sounds while still others blow bubbles, rattle their bones, or clack their jaws.

The noises may communicate mating or spawning information. For instance, a study on the dusky grouper Epinephelus marginatus revealed that low-frequency booms produced by the species may be associated with reproductive displays usually performed during the early stages of courtship behavior.3

Other sounds may be used to avoid predators or for reasons we have yet to uncover. You can hear some fish sounds for yourself using The New York Times links below:

  • Fish sounds, part 1: Clownfish, toad fish, herring, cusk eel, and black drum
  • Fish sounds, part 2: Silver perch, weakfish, spotted sea trout, red drum, Atlantic croaker, oyster toadfish, and striped cusk eel

Fish Get Angry, Feel Pain Too

Fish are greatly underestimated in terms of their ability to feel both emotional and physical pain. It’s likely no coincidence that the French grunt vocalizes when it’s feeling threatened or when it’s caught by fishermen…

Dr. Culum Brown, a professor in the Department of Biological Sciences at Macquarie University, believes fish should be afforded the same level of compassion and welfare as warm-blooded vertebrates, but unfortunately most view them only as food or pets (and as pets, they are often not given the same level of care as dogs, cats, or birds). He writes:4,5

“Part of the problem is the large gap between people’s perception of fish intelligence and the scientific reality. This is an important issue because public perception guides government policy. The perception of an animal’s intelligence often drives our decision whether or not to include them in our moral circle.

From a welfare perspective, most researchers would suggest that if an animal is sentient, then it can most likely suffer and should therefore be offered some form of formal protection.

… Although scientists cannot provide a definitive answer on the level of consciousness for any non-human vertebrate, the extensive evidence of fish behavioral and cognitive sophistication and pain perception suggests that the best practice would be to lend fish the same level of protection as any other vertebrate.”

This also sheds new light on keeping fish in aquariums, which must be done with careful attention to providing a natural, stimulating environment. Fish living in large aquariums with complex (i.e. stimulating) habitat were found to be significantly less aggressive than those living in smaller barren spaces.6

The fish living in cramped, uninspired quarters showed mild disgust by flaring their fins, and displayed more significant anger by chasing, nipping, charging, and even killing one another.

Similar behavior has been observed in sea urchins and great white sharks held captive in small environments. Clearly, some fish become aggressive when placed in confined spaces, and that aggression can wreak havoc on the lives of other fish of the same species sharing the same environment, not to mention, if Dr. Brown’s research is correct, on their own psyche.

Are You Considering a Fish as a Pet?

If you’ve ever had a fish as a pet, you’re probably aware that, like dogs, cats, and birds, each displays its own unique personality. Indeed, research suggests that even fish display individual differences in behavior. Some are shy while others are bold. Some enjoy exploring and are more curious, active, or sociable than others.7

In fact, life experiences, such as winning a fight against a rival, actually alter fishes’ future behavior, much like life experiences alter humans’ behaviors.8 Knowing this, it’s crucial that all pets, including fish, be given a living space that provides not only for their physical needs but their mental and emotional needs as well.

Many small aquariums, and especially fish bowls, do not provide optimal welfare for fish, particularly if you don’t add in stimuli. Larger aquariums with a complex habitat will help to create more natural behavior and, likely, greater well-being in your fish. This includes:

  • Providing ample space – at least 24 square inches of water for every one inch of fish
  • Providing a quiet pump and filter that keeps water clean and flowing
  • Installing an air pump for oxygen and a thermometer to monitor water temperature (this should generally be between 68 and 76°F but depends on the species of fish)
  • Providing items for your fish to explore – plants, rocks, structures, ceramic objects, etc. It’s important to make sure the “furniture” you add to your fish tank is non-toxic
  • Keeping your fish in a quiet area away from loud televisions and radios, and out of direct sunlight
  • Providing the right type of food for the species of fish (fish may vary in their nutritional requirements)
  • Cleaning the tank regularly and using pure, chemical-free water (most tap water contains fluoride, chlorine, and impurities that can harm fish)
  • Taking care not to startle your fish with sudden changes in lighting or noise
  • If your fish seems sick, take him to a fish vet along with a sample of tank water
  • While some fish do better alone, most enjoy companionship and should be kept in pairs (or more)

Finally, when choosing fish for your tank, only buy fish that have been bred in captivity, not those taken from the ocean.