Rita Santos (owner)
Zac (turned into a duplicate of Evie]]
-Has turned into a duplicate of Evie
Poseidon is the cat of Rita Santos in Mako Mermaids. He used to be feared greatly by Sirena, Lyla, and Nixie because they were new to land and was unaware what he was but later knows and accepts him. The cat does later lead the girls to Rita's secret mermaid cave hidden in her office. Poseidon is an exotic male long hair chinchilla. He is Rita's closest friend and companion, guarding her house and possessions and also his very own secret. Podeidon is portrayed by a cat name Monte.
Once Poseidon stepped on some mermaid potions and was able to transform into a human form. Right before he did that he made contact with Evie, and then took her form. Poseidon left the house with David and went to Ocean Cafe and later to the beach, where he got to try chocolate-milk for the first time. He was turned back into a cat by Nixie.