I was curious about it, found this article, and was thoroughly entertained! They can regenerate scilia and receptors!
https://www.geoexpro.com/articles/2011/03/marine-seismic-sources-part-viii-fish-hear-a-great-deal
Here’s a quote:
”Fish do not need an outer or middle ear, since the role of these structures in terrestrial vertebrates is to funnel sound to the ear and overcome the impedance difference between air and the fluids of the inner ear. Since fish live in water, and have the same density as water, there is no impedance difference to overcome. Fish do h