This harlequin shrimp isn t clowning around (yeah, yeah, cue groans).Hymenocera elegans here is found in the waters off of Indonesia. Popular among aquarium enthusiasts for their bright colors, harlequin shrimp are nonetheless tough to care for in a tank. One reason is their diet: They eat only starfish (and sometimes sea urchins), and they reportedly prefer to eat them alive. Since the prey is so much larger than the predator, it sometimes takes the shrimp two weeks to finish off a single (living) starfish. No wonder people think clowns are scary.