The Seahorse is an underwater animal that was first found in the Underwater room during the Cave Expedition. Not much is known about it except that it is small and orange. However, when compared to a penguin's size, it is big. Since the reopening of the Underwater, it still exists. The only other seahorse found in Club Penguin is in an aquarium, in one of Club Penguin's wallpapers.
If you hover your mouse over the seahorse in the Underwater room, it will blow bubbles out of its snout/mouth.