Mermaid

Mermaids are a life state that was introduced in The Sims 3: Island Paradise. They are creatures of the ocean and water, that can be encountered diving or just taking a stroll by boat in the sea. They have also adapted to land living.

Becoming a Mermaid
A Sim can become a mermaid by ingesting mermadic kelp, which can be obtained either by becoming good friends with a mermaid and using the "Ask About Fish Parts" interaction while both the Sim and the mermaid are underwater, or purchasing the Mermadic Kelp lifetime reward for 25,000 lifetime happiness points. Note that other life states cannot turn into a mermaid even if they eat the mermadic kelp. They have to become a normal Sim first to turn.

Mermaid is a genetic lifestate. There is a 50% chance a child will be a mermaid for each mermaid parent.

Even if Supernatural is installed, Mermaids cannot be created in Create a Sim.

Appearance
Mermaids are an acquatic hybrid of fish and Sim. While in the water, mermaids have a colorful scaly fish / dolphin-like tail. Male and female mermaids have different tail shapes; males have straight fins while females tails end in a classic dolphin-shaped fluke. On land, this will transform into a scaly pair of legs of the same color. Mermaids have their scaly legs since the toddlerhood, but they don't morph into a tail until the Sim becomes a teen. The color of their scales can be changed by using the "Change Scale Color" interaction via mirrors. Maybe, you could create Ariel!

In their tailed state, male Mermaids are shirtless and female Mermaids wear seashell bras with a starfish, the color of which can also be customized with the "Change Scale Color" interaction.

Needs
Mermaids needs vary from regular Sims in two ways:


 * Hydration - In place of Hygiene, there is a "Hydration" need, similar to Water for a PlantSim. This can be satisfied by swimming in the ocean or a pool, using the shower or bathtub, or relaxing in a hot tub. If The Sims 3: Seasons is installed, they can also hydrate by standing in the rain. Dehydration will cause the Sim to dry out, giving them a negative moodlet. Eventually they will pass out, and if another Sim does not splash water on them, they will die.
 * Hunger - Mermaids don't get much energy from normal meals. Instead, they live on fish and kelp. Fish can be caught from fishing or while scuba diving, and can be eaten raw. If a Mermaid has the Vegetarian trait, eating fish will make them nauseous. Kelp can be harvested from diving areas or purchased from the grocery.
 * If a Mermaid's hunger need is very low, eating two pieces of kelp is enough to fully replenish it.

Even if a Mermaid is well hydrated, they need to swim in the ocean at least once every 48 hours, otherwise they'll get a "Salt Water Deficiency" moodlet. Within a day this will turn into "Adapting to Land" and when this moodlet expires, the mermaid will turn into a normal Sim. Purchasing the "Permanent Mermaid" lifetime reward will prevent the Mermaid from losing their occult status.

Abilities
Mermaids have various water-related special abilities. They can breathe and stay underwater indefinitely, and will not get the "Depressurising" moodlet when returning to the surface. This makes the Steel Lungs lifetime reward useless for them. Mermaids swim much faster than normal Sims, both underwater and above. Once a mermaid becomes a teenager they will automatically maximize their Scuba Diving skill.

Like normal Sims, mermaids who possess a conch shell are able to summon another mermaid they have met. Mermaids with the the Evil trait are able to summon sharks to attack other divers. Mermaids are perfectly safe in the sea and cannot be attacked by the Kraken, cave monster and sharks.

Hidden Island
One of the hidden islands in Isla Paradiso can be unlocked by becoming good friends with a mermaid in one of the diving areas. After befriending them, the mermaid will come up and offer to show the location of mermaid's secret island, and then the player will unlock it.

Trivia

 * The mermaid was mentioned in The Sims Medieval, in one of the random events in docks.
 * The Sims 3: Seasons has two clothing pieces and a hairstyle which have a look akin to a mermaid.
 * Just like other life states, Mermaids cannot become another creature without having their Mermaid status revoked first.
 * Mermaids cannot skinny dip in a hot tub, but can still WooHoo.
 * Some mermaids can have pale skin like vampires.
 * Mermaids can not get a tan.
 * Pregnant Mermaids can swim at the water's surface, but cannot visit underwater dive lots for the duration of the pregnancy.
 * If a Mermaid goes into labour, they can't have their baby in the sea, they must go to land to give birth, and Mermaid babies must grow on land.
 * There are several minor references to Disney's The Little Mermaid. Some premade mermaids are based on characters from the film, such as Triton King and Mia Azul. When a Sim explores an underwater cave, sometimes a message appears saying, "(Sim's Name) has not found anything big, but he/she found a dinglehopper," or "how many wonders can one cavern hold?"
 * Mermadic Kelp can also be purchased through buy mode, with the buydebug cheat on, for §0.