Other unusual characteristics of a seahorse are its upright stance, with its prehensile tail — which allows it to hold on to coral and other sea objects. Their tiny size, usually less than 15 centimeters, gives them a "jewel-like" appearance. And seahorses don't have the scales of typical fish; instead they have a dark, exo-skeleton of bony plates for protection and camouflage.
Source: tatoeba (12219788)