🐟👂🏻 Do Fish Have Ears?

No, fish don’t have ears as humans do but they do have inner ears. Fish can hear the sound by using the auditory organ (otoliths) and the lateral line system. Some fish have enhanced hearing sense due to the presence of a swim bladder. Typically a fish has a hearing capacity in the range of 1 Hz to 1.5 kHz. Hearing is an important sense for the survival of the fish. Fish use their hearing sense to find food, habitat, and mating partner. Some fish with poor vision or living in deep dark oceans rely heavily on their auditory organs to catch prey and escape from predators.

Can fish hear?

Have you ever seen the earlobes of fish? No, right!

Fish don’t have earlobes as humans do but still fish can hear the sound. Yes, you cannot see the ears of the fish but they are present inside the head. Hearing is one of the essential senses in the fish to survive. Hearing sense helps fish to find food, to attract partner mate, to prevent danger, and in many more ways. Note that the hearing range of the auditory sensitivity of fish varies with different species of fish. Let’s try to understand the auditory organ of the fish.

How do fish hear?

Before, we learn how fish hear sound, let’s recall how do humans hear?

In humans, we have a pair of ears through which sound waves enters into our head. These sound waves travel through a narrow passageway called the ear canal and reach the eardrum. The eardrum starts to vibrate due to these incoming sound waves. The vibrations of eardrums are passed to three tiny bones (malleus, incus, and stapes) in the middle ear which amplify the sound vibrations and send them to a snail-shaped structure in the inner ear called the cochlea. The vibrations of fluid inside the cochlea are detected by hair cells (sensory cells) present near the cochlea. The hair cells move up and down as per the vibrations. Note that different hair cells are tuned to respond to different pitch and frequency of sounds. These hair cells convert these vibrations into electrical signals that are transmitted to the brain through auditory nerves.

Read: 🐡💕 How Do Fish Mate?

Fish have more than one organ that helps them to detect or hear the sound. In the case of fish, we cannot see ear-opening but they do have an auditory organ in their head to sense vibrations in the water. Many fish use their otoliths, lateral lines, and swim bladder to hear the sound.

Otoliths in fish

Fish have inner ears in their head that contains structures called otoliths. These otoliths are made up of calcium carbonate structures that are denser than the water and the fish’s body. When the sound waves hit the body of the fish, these otoliths move at different amplitudes and wavelengths than that of the fish body due to difference in density. The movement in the fish body causes the hair cells (sensory cells) to bend. Then, these hair cells convert these movements into electrical signals which are sent to the brain. The brain compares the movement of hair cells and the otolith to detect the sound. In this way, otoliths help fish to sense both horizontal and vertical linear acceleration. Fishes with defective otoliths lack the ability to sense motion as well as orientation to gravity properly.

Position of the otoliths within the inner ear of Teleost fish. (A) Dorsal view of the labyrinth system in a typical Teleost species. The top of the cranium is cut away (frontal section). (B) Otoliths within the labyrinth systems of a typical Teleost (Image credit: Hélène De Pontual)

You will be surprised to know that the age of fish is estimated by counting the annual growth rings on the otolith.

Read: 🦈 Do Fish Blink?

Lateral lines system in fish

Fish have a sense organ called canal neuromast located along the lateral line of the fish. These neuromasts are mechanoreceptive organs that allow sensing of mechanical changes in the surrounding water. Each neuromast is consists of hair cells covered with a cupula, a flexible and jelly-like cover. Whenever there are any changes in the surrounding water, these cupulas bend and the hair cells detect and convert these vibrations into an electrical signal which is transmitted to the fish’s brain.

Lateral Line Organ, Image credit: Thomas.haslwanter

In this way, sense organs of the lateral line detect the vibrations and the pressure gradient in the surrounding water. These lateral lines play important role in the survival of the fish. They help fish in schooling behavior, predation, and orientation.

Lateral Line, Image credit: Pogrebnoj-Alexandroff

How swim bladder enhances hearing in fish?

We know that the swim bladder is an air bladder filled with gases that help to control buoyancy. Using these swim bladder, fish can change the depth or stay at the current depth without wasting energy in swimming. Along with this, the swim bladder also plays important role in enhancing the hearing ability of the fish. However, the auditory sensitivity depends on the proximity of the swim bladder near the inner ear.

Read: 🦈Do Fish Have Tongues?

The swim bladder mainly consists of gases which are less dense than that of the seawater and the fish body. Any change or vibrations in the surrounding water can easily compress these gases in the swim bladder. The vibrations due to the change in the volume of the swim bladder can stimulate the hair cells present in the inner ear. These hair cells transmit the sound information to the fish’s brain in the form of electrical signals. Therefore, the presence of a swim bladder near the inner ear can enhance the hearing range of the fish.

Internal organs of fish, Image credit: Sharon High School

Some fish such as carps and catfish have structural modifications that conduct the sound from swim bladder to inner while there are some fish such as squirrelfish and butterflyfish in which swim bladder extends such that it comes in contact with the inner ear.

However, note that not all fish have a swim bladder. Fish such as elasmobranchs and flatfishes have poorer hearing sense due to lack of swim bladder.

Read: 🐠 Can Fish Drown?

There are also some fish such as tuna and Atlantic salmon which do not have extended swim bladder or modified structures to between the inner ear and swim bladder. These species also have poor hearing capabilities.

How fish use hearing sense for survival?

Hearing sense plays important role in the survival of the fish. Many fish use this sense in different ways for different purposes. Some of the common reasons are

  • Fish can sense the presence of their predators. Therefore, they can easily escape the attack from the predator.
  • Fish can rely on their auditory organs to find and locate their habitat.
  • Fish also depends on their hearing sense for finding their food. Fish can easily sense and catch the prey by their vibrations.
  • Fish can attract and communicate with their partners for mating.
  • Fish use sound to stay together and form a shoal during spawning and night time.
  • Fish produce different sounds to alert the members of the shoal about the danger.
  • Fish use their hearing senses to orient and navigate during migration.

Read: 🍣 Do Fish Have Blood?

Here are some fishes which use their hearing sense in interesting ways:

  • Juvenile fish can sense the sound coming from different habitats to navigate during night time.
  • Male midshipman fish produce sounds to attract female midshipman fish. It is interesting to note that only fertile females get attracted to these sounds and lay eggs in the male fish’s nest.
  • Atlantic and Pacific herring fish produces high pitched farting sound to communicate with other fishes. They mostly produce sound at night time to form a shoal.

Now if you are wondering can we talk to fish?

Can fish hear you talk?

Yes, some fish may be able to hear you but won’t be able to understand our language. It is also possible that some species of fish may not be able to hear you because the hearing capabilities vary with different species of fish. Typically the hearing frequency of the fish is not more than 800–1000 Hz while the frequency of voice speech of a typical human male varies from 85 to 185 Hz ranges in and that of a typical adult female from 165 to 255 Hz. Therefore, fish can easily detect the sound produced by humans.

The hearing range of fish

Fish nameFrequency (Hz)
Wild and adult salmon100 to 800
Goldfish20 to 4000
Sharks10 to 800
Tuna200 to 800
Cichlids300 to 500

Read: 🐟 How Do Fish Taste?

Factors affecting hearing sense of fish

There are many factors that can affect the hearing capabilities of the fish in the ocean.

  • The noise produced by large ships and submarines can cause a disturbance in the ocean water. Fish may not able to detect the sounds accurately due to the interference of external sound vibrations. The inaccuracy in the detection of sound waves can make them prone to the attacks of predators.  Fish might find it difficult to find food and habitat. They might also struggle with orientation or navigation in the ocean.
  • The otoliths in fish are made up of calcium carbonate. Ocean acidification can lead to an increase in the size of otoliths. This increase in the size of otoliths can lower the hearing ability of fish because a proper balance between otolith shape, size, and structure is required for hearing capacity.

Can goldfish hear?

Yes, goldfish can hear. Goldfish have both inner ear with otolith and lateral line. Goldfish have the ability to hear frequency from 20 to 4000 Hz.

Can betta fish hear?

Yes, betta fish can hear sounds by both inner ear and lateral line. Due to poor eyesight, betta fish rely on their auditory senses to survive. They use the lateral line to sense the vibrations in the surrounding water.

Read more interesting questions about fish:

Professor Atom

View posts by Professor Atom
Professor Atom is a science enthusiast and alumni of IIT Bombay. According to him, every question can be solved with curiosity and mind mapping. ( Curiosity = Asking Questions = Learning )

2 Comments

  1. Jersey Mikes LocationsNovember 7, 2020

    Nice article and I really appreciate your work.
    King regards,
    Thomassen Zacho

    Reply
    1. Professor AtomNovember 8, 2020

      Thank you, Laurence, for your kinds words =D

      Reply

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