Harlequin shrimps are monogamous, living in male-female pairs for life, sharing and actively defending a patch of reef of about 10 square meters. Asides from their exquisite colour patterns and their highly aberrant morphology, they are predatory carnivores, feeding on various starfish species. Prey is located by either member of the pair, being often more than 10-20 times larger than the shrimps, flipped over and dragged to their lair. The internal organs (tube feet, guts) are devoured, starting from the tips of the starfish’s arms and working their way to the central disk, thus keeping their victim alive for as long as possible. It usually takes several days for the process to be completed. On occasion a starfish escapes, minus a leg or two, but usually they succumb. A large scale program was initiated in the eighties to attempt to harness this behaviour as a bioweapon against Crown-of-Thorn outbreaks in the Pacific. Due to their antagonistic territorial behaviour this was doomed however, as each pair of shrimp would kill all the others in close vicinity.
Sammy De Grave, Zoological Collections