This tricolored egg has a wiggly fin poking out of it.
Hatchling
From the moment they hatch, serterix hatchlings are on the move. They do not yet possess the strength to traverse the open ocean, but their speed is nearly unmatched in the reefs where they hunt for their first few years of life. Their favorite prey is small fish, and serterix hatchlings will use their burgeoning abilities over light to create eye-searing displays that will confuse a fish into being an easy catch. As hatchlings cannot travel far early in life, they are aggressive about staking out territories, and tend to be intolerant of others of their species. To mark their own territory, they create swirled designs in the sandy ocean floor with their bodies near the entrance to their chosen dens.
Adult
As serterix grow into adults, their temperaments toward one another mellow. The territorial marking that hatchlings do is actually the beginning of a complex communication system. Instead of using their sand designs for aggressive territorial posturing, they will plan group hunts, becoming a unified pack. They can often be seen gathering in small groups at reefs, and using complex swirled designs in the sand, the group will agree on their next hunt. Sometimes, the designs become even more complicated, looking almost like a written language, and they will venture out on long journeys. Sometimes they simply travel along the shore, but it is common to see groups crossing the ocean. It is believed they travel simply to explore, as they have been sighted as far north as the cold waters of northern Arkene, though they don't stay long there. Many magi have studied their markings in the sand, but there seems to be no meaning to them that humans can understand, and the patterns look different every time.
General description
Spoiler
Skilled with light magic, serterix can light up their bodies and their scales will ripple with pulsing, high-energy blue light. This is often done to confuse and stun prey, but also to communicate. While they will use sand to form designs when they can, in the absence of sand, they will communicate with the group using spectacular light displays underneath the waves. This is most often seen during hunts, when fast communication is necessary, and flashing lights in the water often mark serterix carrying out a hunt of large prey. Except on reefs, serterix swim near the surface, where their shiny scales and fins catch the light and sparkle. This is important for males, as females select a mate based on a male's scale and fin quality, an indicator of health. Although serterix are quite large, females are still noticeably larger than males. Females will aggressively defend their small clutches of eggs, laid on the ocean floor in a shallow nest, until they hatch. Serterix are not common magi companions because they prefer to be able to travel and associate with others of their species, but fishermen and seafaring magi befriend them on occasion.
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Not sure if there's dimorphism yet, grew a single one using chocolates
