Now that they know some fish can see red, ichthyologists might be a little red in the face.
Because water tends to absorb long wavelengths of visible light, long-wavelength red photons don’t penetrate much past the top 30 feet of ocean. So fish experts had assumed that red just wasn’t part of the underwater world, and fish probably couldn’t see it. But a new study led by German researcher Nico Michiels concluded quite the contrary—numerous species of fish can produce their own red light through luminescence.
