Order: Concavolateriformes
Family: Challiaichthyidae
Genus: Challaichthys
Fig. 1: A brawbro (Challaichthys grandis). Note the orange, concave lateral surfaces of the prosoma.
Grey and purple with a splash of orange on its prosoma, the 1.25 metre long brawbro is distinctive in first sight. Whether be its aggressive, antisocial behaviour, or the fact that its anatomy is just plain weird, the brawbro is truly one of the more unique species of pelagys.
By far the most unusual aspect of the brawbro's anatomy is the form of the prosoma. Whilst most pelagys retain a relatively fusiform build with outward-curving sides, the brawbro has extended dorsal and ventral surfaces, with the sides of its prosoma being concave, curving inwards. The concave surface is a bright orange in colour, which is presumably for display. However, it isn't known why the sides are concave; the leading theory is that it makes the gills harder to access from predators. The feature appears to be present in all its extinct relatives.
Aside the strange, concave prosoma, the brawbro possesses large tail muscles, which are easily visible on the living organism. These powerful tail muscles propel the brawbro to high speeds, allowing it to accelerate quickly, with a homocercal, strongly forked posterior caudal rhachises an adaptation for high speed swimming, allowing it to hunt prey such as chovies and engrads, which hunt in shoals. The large, rigid pectoral, dorsal and ventral fins are specially adapted to control its movement in hide speed, and it can fold them back to achieve exceptionally high speeds.
While these adaptations are typically seen in pelagic species, the brawbro tends to stick closely to coastlines, specifically in rocky drop-offs, ranging from depths of 15m to 100m, sometimes near undersea caves. Often, at deeper depths, they remain remarkably calm, when in solitude.
Rarely seen in reefs or equatorial savannahs, they aren't a very common sight, and when they are spotted they are always alone. They are very antisocial and aggressive, especially towards their own kind, and to other species as well. Most evident during hunting, they often bully smaller crescentjacks away from large schools of pelagys, in which a single brawbro will hunt for itself. Aside from that, they also bully away scavengers or small predators from their kills and attack other species that simply get too close. The only species that they do tolerate are larger aeunas, stickyfins and doctorfish, which they allow to come close, but they are very snappy, even to these species.
While the brawbro is very aggressive and obnoxious, its not necessarily dumb enough to go against aeunas, which can be twice its size. It isn't so much foolhardy, more so that it appears allergic to anything weaker than it being within a metre of itself.
But despite its ornery behaviour, the brawbro truly is a survivor. It is capable of eating pretty much anything aside from live prey, and it is aggressive so it monopolises resources — a survivor from an older age. For much of its own clade has become extinct in the past 10 million years, leaving the brawbro alone as the only surviving member of its clade. But it continues to survive until this day, thriving, whether it be stealing food from weaker species or leisurely swimming in solitude at depths of a hundred metres.