Key open questions in zebrafish auditory biology include: (i) the precise molecular mechanisms of MET channel gating and modulation; (ii) the dynamics and regulation of tip link regeneration, and how zebrafish-specific mechanical properties compare to mammals; (iii) the functional significance of subtype-specific expression patterns of MET-associated genes in auditory versus vestibular hair cells; and (iv) the cellular and molecular pathways enabling regeneration after hair cell loss caused by mutations that lead to permanent deafness in mammals. The gene discussed is MET; the disease is deafness.