I don't know about 'by hue' but almost all colors are not in the rainbow. The spectral locus is a line that runs around the edge of a 2D color space (technically 3D if you include luminance as well...).
7D if you are a mantis shrimp.
7D if you are a mantis shrimp.
Don't be sure:
* https://www.popsci.com/blog-network/ladybits/mantis-shrimp-v...
* https://phys.org/news/2014-01-mantis-shrimp-vision-different...
Though they do see polarization, which is a neat feature.