[End the story with this sentence] “Behold... the mighty predator.” -- TheDragonsFlame
First came the epithelials, and there was the Dust Problem. Amelioration worked, to a degree, but cleansing schedules soon became hell for multiple species. And someone discovered Fhitts and Squidges. Small, jellyfish-like animals that floated around via hydrogen gas bags. They either filter-fed as they drifted around on the air currents, or -in the case of the Fhitts- jetted about in active pursuit.
Then the Fhitts and the Squidges became popular. Cleansing schedules were eagerly jettisoned. Until an overpopulation problem caused both to clog the air filters. Something, plainly, had to be done. Filter patrols and culls were initiated, and a careful balance was difficult to maintain.
And then someone discovered Oshits. Decapodal, exoskeletal, insectoid predators that hunted by chasing down anything that disturbed the air currents. They were death on Fhitts, and some sub-species evolved to capture Squidges. And, for a while, things were easier. Filter patrols toned down. Culls were unnecessary. But the price to pay was the occasional spider-mimic landing on the face or the body.