For a fishkeeper this question often arises while trying to talk to your fish, can fish hear us? Do fishes have ears?
Yes, fish do have ears and they can certainly hear the noise.
The answer is quite simple you can even witness this yourself if at night your fish is sleeping and there is a loud sound nearby, your fish will respond to this sound. This is proof that fish do have ears and hearing abilities.
Not just that we know that fishes are blessed with all the basic senses such as vision, hearing, taste, and touch.
Today we will learn about the anatomy of fish’s ears and their modification according to different habitats.
Let’s dig into this topic without any further delay.
Anatomy of Fish’s Ears:
Fishes don’t have external ears or earlobes that indicate the presence of the auditory system, but they do have an internal ear. Important structures that we will discuss regarding the fish’s auditory system are Otolith and swim bladder.
There are two basic pathways of sound detection in fish.
- Auditory system
- Lateral line system
Inner Ear in Fish:
It is quite clear from the gross appearance of fish that do not have external ears and there is a reason for that that is explained later. Fishes do have internal ears that are formed of the otolith.
The internal ear is involved in the auditory pathway of sound perception. Different components and general pathways of the authority system are following.
Auditory System in Fishes:
The auditory system in fish is somewhat similar to that seen in mammals with the perception of sound waves in terms of vibrations. These vibrations result in the movement of cilia in the hair cells.
The movement of cilia is interpreted as nerve impulses and is sent to the brain via the glossopharyngeal nerve. These impulses later result in the detection of sound.
The Otoliths and swim bladder are the main components of the auditory system, and they are now discussed in detail.
Ear stones or otoliths are the most important components of the inner ear. They are made up of calcium carbonate thus are known as stones. The principle behind otoliths being an organ of sound perception is the difference in density.
Working of otolith:
Generally, fishes are nearly the same in density to water, whereas otoliths are quite higher in density. When sound waves in the water pass through the body the amplitude of vibration causes differential movement in the fish’s body than that of the otolith.
This difference in movement, in turn, results in the movement of cilia on hair cells present in the inner ear. This differential movement is interpreted as sound in a fish’s brain.
-Swim bladder is an organ of buoyancy; it is filled with gas and helps the fish in floating and swimming. A question arises here that what is the relation of the swim bladder with a fish’s auditory system.
The range of frequencies detected by fishes depends on the relative position of the swim bladder to the inner ear. There are different modalities of sound perception depending on the presence, absence, and location of the swim bladder.
Working Principle of Swim Bladder:
As swim bladder is filled with gas and this gas is easily compressed upon exposure to outside pressure displayed by the sound waves. Once the swim bladder is compressed to the limit that it reaches the inner ear and results in the movement of hair cells, the rest of the pathway is the same.
The involvement of hair cells and relative movement of cilia results in nerve impulse generation and ultimately sound is detected.
Sound Perception Based on Swim Bladder:
According to different research conducted on the presence, absence, and relative location of the swim bladder to the inner ear it has been found that this does affect the frequency and amplitude of sound waves detected. These studies are based on different groups of fishes based on their anatomy.
Fish Species Without Swim Bladder:
Species lacking swim bladder at all are shown to have decreased ability to perceive sound waves and have a narrow range of audible sound. Some of the flatfishes, sharks, skates, and rays don’t have swim bladder at all. Thus, their ability of sound detection is greatly minimized.
The only way of sound perception in these species is through the lateral line system.
Fish species in which swim bladder is connected to inner ear:
Adaptations are continuously occurring in the underwater world. Some of the fishes such as catfishes, characins, and carps have modified anatomical structures. Weberian ossicles are bony structures that connect the swim bladder to the inner ear.
These ossicles are proven to improve the quality of sound perceived. A prominent effect is seen in Goldfish where the audible frequency is raised to even 3000Hz all thanks to these mini ossicles.
Fish Species without swim bladder extensions:
In some species, there are well-developed extensions from the swim bladder reaching the inner ear. Certain cods, butterflyfish, and squirrelfishes are equipped with these extensions and have better developed auditory systems.
The reason behind enhances sound quality is that sound waves have to travel a short distance to reach the inner ear and loss of waves is minimized. Thus, overall better sound perception is seen in these species. The maximum sound frequency received in these species is around 1000Hz.
Fish Species Having Gas-Filled Tubes:
Some species such as anchovies, shads, and sardines have special structures responsible for the conduction of Most marine creatures can’t hear sounds of frequency greater than 1000Hz but these clupeiform fishes can detect sounds of frequency more than 3-4KHz. This audible range is impressive and is all due to the presence of these structures. sound waves to the inner ear and brain. There is a pair of gas-filled tubes that are in direct contact with the utricle of the inner ear.
The close proximation of these tubes results in better stimulation of the inner ear by the swim bladder thus increased sensitivity of sound. The presence of this structure has increased the audible frequency by 2-3 folds.
Lateral Line System of Sound Conduction:
The lateral line system is also based on the perception of sound through the sound waves (vibrations) in water, but the pathway and components are a little different.
The head, trunk, and tail of fish are laden with hair cells just like seen in ears. These cells have cilia as well and are embedded in a gelatinous capsule called the cupula. The movement of these hair cells in the cupula results in the detection of sound waves and their interpretation to sound.
These hair cells are components of an organ called neuromast that is present along the body in two lateral canals. The vibration sensors are located all over their body in the form of canals. As the sound waves approach, they are detected by these neuromasts, and sound of variable frequency is perceived.
Why Fish Don’t Have External Ears?
If you take a look at a fish, you will notice that they lack external ears. The fact that they don’t have ears outside their body makes us wonder whether they can hear or not.
This is made clear that fish do hear a wide range of sounds but now the question is why they don’t have external ear structures. The reason is that fishes don’t pick up sound waves from their ears so quite there is no external opening.
Fishes have a unique ability that they can pick up sound waves from water through their bodies. This is feasible as water has 4 times faster sound transmission ability than air. Thus, sound waves travel much faster in water and can produce the sensation of sound.
Thus, fishes don’t need external ears.
Which Frequency of Sound Is Audible for Fish?
There is a variable range of frequencies a fish can detect. The lowest audible frequency is 50Hz and it can reach up to the highest limits depending upon the species and its internal structure.
The maximum frequency perceived in most species is 1000Hz. Goldfish and herrings can hear voices of frequency reaching 3000Hz.
Moreover, fishes such as cods and clupeid can perceive ultrasonic sounds.
Factors Affecting Fishes Hearing Ability:
Several factors affect the hearing ability in fish. Habitat, neighboring species, and climate play a great role in sound perception. Many species have evolved according to their environments such as high-water waves, frequent rain, storms, or any geological event.
Moreover, the anatomy of fish such as the presence or absence of the swim bladder, its location, and extensions can improve or block the sound perception in fish.
Benefits Of Hearing Ability in Aquatic World:
The acoustic sense in fish is greatly valued in the underwater world. From studies, it is proven that fish can access more about their environment from their sense of hearing than their sense of vision.
Any incoming predator or prey nearby can be easily detected by the frequency of sound waves produced by their motion. Furthermore, any incoming obstruction in their pathway such as rocks, reefs is detected by these sound waves.
Thus, sense of hearing can provide lots of useful information to fishes about their environment.
Frequently Asked Question (FAQs):
Yes, fish is quite capable of hearing us talking to them. Although they might not be able to interpret, indeed, your fish can certainly hear you.
Yes, fish do have ears that are located inside their bodies. They have both auditory and lateral line systems for sound perception.
In the end, it is safe to say that fish do have ears and they can hear us and other sounds in their environment. Apart from hearing fishes are equipped with other basic senses as well.
Sound detection in fish is a nature’s marvel and is best adapted to fish’s environment.
I hope this article cleared up all the confusion and answered all the queries.
Best of luck with your fish!!!