The "I'm in heat" meme gave us an idea... why is Plasmius so different from Masters? Why is his upper body so big? What is the reason for his ghost's teeth and unnatural colors? There is an animal in nature that undergoes extremely similar changes...
And would that mean these are breeding colors/spawning colors?
The upriver spawning migration of the Atlantic and Pacific salmon involves drastic skeletal alterations, including the development of extremely large teeth (also called "breeding" or "fighting" teeth)
AUTUMN 2001 ATLANTIC SALMON JOURNAL 37
"Sex can have enormous effects on teeth and bones. The bones and teeth of Atlantic salmon undergo drastic changes during the animals’ upstream spawning migration. A new set of teeth, referred to as “breeding teeth”, replace the feeding teeth. Despite the name, the role these teeth play in breeding is unclear. The bones and cartilages of the skulls of male (and to a lesser extent, female) Atlantic salmon, also exhibit dramatic changes during the spawning migration. All the bones of the skull change in some way, but some much more dramatically than others."
Sockeye turn bright red on their body, and olive-green on the head. Males develop a prominent hump in front of the dorsal fin.
We'll probably elaborate more later.
(Yes, we have a passion for salmons. We are even creating a species of salmon merfolk XD. So, yeah, sockeye breeding colors go brrr)