Imumoslontus abyssus

From OurFoodChain

Descended from a population of O. enjambre that moved away from their primary diet of T. longiceedus and fed more and more on organic matter in the sediment to as a result of intraspecific competition as populations grew in size and threatened overgrazing. They moved into deeper parts of the lake where the organic matter was most abundant and undisturbed by other organisms.
6-8 centimeters long

Being nearly blind, since they don't really rely vision and their ancestors had poor eyesight, O. abyssus relies quite heavily on its peripheral chemoreceptors to navigate its surroundings. As they rely more on them, they have become more abundant and developed. Their biggest changes are the tooth-like barbs that grow on their lower jaw. These barbs first started out as small serrations of the skin that grew longer and eventually got covered in a layer of calcium. These barbs assist in feeding, which they do by raking their moves through sediment and using the barbs to filter organic matter out of the particles. The barbs prevent larger inorganic particles such as pebbles from being swallowed and whatever small inorganic particles do get swallowed pass through the gut.

Much like their ancestors O. abyssus will sexually reproduce in large "orgies" with males and females mating with multiple partners once a month. Females also inherit the same wombs to store unfertilized eggs before releasing them while mating, typically producing around 180-200 eggs on average. O. abyssus take longer to mature then O. enjambre, taking two and a half weeks to get to adult size. Due to their predators being less abundant in the deeper waters of the lake, O. abyssus were able to grow slightly large on average then their ancestors; this adaptation allows them to have a larger surface area for chemoreception. Due to their less caloric diet O. abyssus live slightly longer on average as well, living close to eight months rather then the mere six months of O. enjambre.