Hippocampus

Hippocampi (singular is Hippocampus) are from the waist up stallion horses and from waist down have a fish tail. One has taken a liking to Tyson, and he named it Rainbow. They are also called "fish ponies" by Tyson.

Appearances
They first appear in The Sea of Monsters, taking them to the Princess Andromeda, and appear again in The Titan's Curse, when they alert Percy of the Ophiotaurus trapped in a net. They also appear in The Last Olympian when they help Percy, Annabeth, and Nico get to Camp Half-Blood. Tyson seems to get along with hippocampi and named one hippocampi "Rainbow".

Trivia

 * Percy refers to the hippocampi as "not all that smart".
 * They refer to Percy as "My lord" because their creator was Poseidon237px-Sea-monster_Terme_di_Nettuno_Ostia_Antica_2006-09-08.jpg
 * They often rely on Percy to help them. That is how he first met the Ophiotaurus (with them asking him to free it).
 * The term 'hippocampus' is a part of the brain, which is ironic since Percy said that they are not intelligent.
 * Hippocampi are said to be able to dash through the water very fast.
 * They can be used as beasts of burden.


 * Poseidon's chariot is pulled by hippocampi.
 * In The Sea of Monsters, one of the hippocampi that Percy, Annabeth, and Tyson meet to get them to the Princess Andromeda is Rainbow, who rescues them after Polyphemus destroys their ride, the Queen Anne's Revenge, a pirate ship owned by Blackbeard, son of Ares, when Clarisse kept taunting Polyphemus as Percy desperately swims for the side of the Queen Anne's Revenge
 * Tyson calls the hippocampi "Fish Ponies".