The filterfan repaced its ancrestor the fan ureel. Due to the lack of food and strong competition at the bottom of the ocean they were eventually pushed out. The fan ureels migrated to the western coast of Wright where food was more abundant. There they grew to double their ancestors size and developed a rusty color to match the sand. To filter-feed easier their filtering tail split into 5 separate branches each with their own miniature filter tail on each one. It will wave each around scooping up the water and filtering out food.
They stay immobile most of the time however can uproot themselves out of the ground and swim in a serpentine motion. They will do this if food is scarce and when mating. When returning to the sand it will first swim upwards, then dive downwards at high speed. With its tentacles pressed together, it forces itself into the sea floor.
Filterfans have developed a bio-electric shock when predators try to bite them. This will usually scares off any would be predators. Since they are blind and can only sense each other though touch and bio-electric senses on the sides of their body. Males with stronger electric fields will be chosen by females.