Above is a sped up video of an Asterina starfish crawling around on the glass, grazing on algae along the way. These starfish aren’t anything rare or unusual, hence the enhanced speed and up-tempo music, but we certainly have an appreciation for the cleanup crews in our aquariums. The Asterina usually enter an aquarium by hitch hiking in on a coral frag from a more established aquarium. These stars multiply very rapidly, simply by splitting over and over again. They often exhibit weird shapes and a random number of arms, making them appear like a strange and potentially dangerous pest to the unknowing aquarium hobbyist.
When populations of these starfish get too large, they can block out light to corals, causing small lighter colored spots to develop. Fortunately, there’s a rather gorgeous invertebrate that many hobbyists used to eat these stars, the harlequin shrimp. While these shrimp usually go after larger starfish, some hobbyists have expressed success when using them to control these tiny sea stars.