Be Careful What You Say Around Your Fish

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Fish Connoisseur
Dec 31, 2004
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Ladich, F. (2023). Hearing in catfishes: 200 years of research. Fish & Fisheris. First published: 20 April 2023

Ernst Weber stated in 1819, based on dissections, that the swimbladder in the European wels (Silurus glanis ', WIDTH, 320)" onmouseout="UnTip()" target="_blank" rel="noreferrer">Silurus glanis, Siluridae) and related cyprinids serves as an eardrum and that the ossicles connecting it to the inner ear function as hearing ossicles similar to mammals. In the early 20th century, K. von Frisch showed experimentally that catfishes and cyprinids (otophysines) indeed hear excellently compared to fish taxa lacking auxiliary hearing structures (ossicles, eardrums). Knowledge on hearing in catfishes progressed in particular in the 21st century. Currently, hearing abilities (audiograms) are known in 28 species out of 13 families. Recent ontogenetic and comparative studies revealed that the ability to detect sounds of low-level and high frequencies (4–6 kHz) depends on the development of Weberian ossicles. Species with a higher number of ossicles and larger bladders hear better at higher frequencies (>1 kHz). Hearing sensitivities are furthermore affected by ecological factors. Rising temperatures increase, whereas various noise regimes decrease hearing. Exposure to high-noise levels (>150 dB) for hours result in temporary thresholds shifts (TTS) and recovery of hearing after several days. Low-noise levels reduce hearing abilities due to masking without a TTS. Furthermore, auditory evoked potential (AEP) experiments reveal that the temporal patterns of fish-produced pulsed stridulation and drumming sounds are represented in their auditory pathways, indicating that catfishes are able to extract important information for acoustic communication. Further research should concentrate on inner ears to determine whether the diversity in swimbladders and ossicles is paralleled in the inner ear fine structure.

Sound detection​

While the basic anatomy of the catfish and other fish inner ears were known at the end of the 19th century (Retzius, 1881), the question remained whether fish are able to hear sound. Fish reacted or did not react to loud artificial sounds generated by bells or whistles in the air or to plucking strings attached to aquaria (Parker, 1918). Ultimately, a catfish helped to answer the question unequivocally. A brown bullhead named Xaverl was regularly fed while the future Nobel laureate Karl von Frisch was whistling. After some time, the catfish swam to the water surface as soon it heard a whistle – without any further stimulus (Von Frisch, 1923). Using this food reward conditioning, numerous species from various taxa including minnows, pikes, perches, trout, eels and others consistently responded to artificial sounds, proving that fish have a well-developed sense of hearing (Von Frisch, 1936, 1938). Von Frisch and his collaborators furthermore demonstrated that otophysines hear much better than other taxa – even better than humans under similar conditions. Brown bullheads and Eurasian minnows in aquaria responded at greater distances to whistles than humans in aquaria (Figure 3) (Stetter, 1929). Both catfish and minnows could be trained to discriminate between pure tones of different frequencies (Tavolga, 1982). In addition, Von Frisch showed that removing the swimbladder in minnows reduced the “acuteness of the sense of hearing very much” (Von Frisch, 1938).

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Experimental setup demonstrating that catfish (and minnows) hear better than humans under similar conditions. Brown bullheads detected whistling sounds at distances of up to 65 m (minnows up to 75 m) as compared to 50 m in humans. The future Nobel laureate Karl von Frisch is standing on the left. Experiments were conducted in a 120-m-long hallway at the Institute of Zoology at the University of Munich. From Stetter (1929).


Fish Fanatic
Mar 1, 2023
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Houston, TX
My fish must have come to love music. I play alot of it from my computer and my tanks are all close proximity to it. Espcially my 20 gallon. Thanks for the post I always wondered if they could hear only only feel vibrations from the music.


Fish Aficionado
Oct 14, 2011
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Eastern Canada
We're the animal that can't see or hear sometimes. We're concerned about artificial intelligence and still generally have no clue about the natural intelligence and abilities of the other creatures around us. As research like this moves along, we have to see we aren't the only talented animal out there.

My fish react to the arrival of people they can't see yet. They tend to be shy species, and they hear arrivals. That was when new people enter the fishroom, they hide and it can look like I have no fish....

I think I have seen reaction to music. It would probably be a sensible adaptation to be able to hear birds if you were a fish, since birds are one of life's great dangers for small species and young fish. I don't think I'll ever see a shoal of cardinals come out of the weeds and do a coordinated dance routine, although maybe they do and I don't understand their moves...

I am a music freak, and often the fishroom has music playing the whole time I'm in it. I figure the killies sit in their tanks wondering how in the world those punk birds ever find mates with their lousy singing voices.

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