Mermaid

Mermaids are a life state that was introduced in The Sims 3: Island Paradise. They are creatures of the ocean and water, but they have also adapted to land living.

Becoming a Mermaid
A Sim can become a Mermaid by ingesting the special mermadic kelp. Mermadic kelp 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 by purchasing the Mermadic Kelp lifetime reward which costs 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 characteristics, like most other life states are genetic. Thus meaning that if a Mermaid has a child with a human or an other type of supernatural creature, the child will have a 50% chance to either be a Mermaid or be like the non-mermaid parent. If both parents are Mermaids, the child is guaranteed to be a Mermaid as well.

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

Appearance
On land, Mermaids look no different than normal Sims. Although there is one easy way to distinguish a Mermaid from a normal sim, and that's by their legs.

Mermaids have colorful scaly legs while on land. The scales first appear when a Mermaid Sim reaches the toddler stage. Although children and toddlers have scaly legs, they do not morph their legs into tails when they swim in the pool or the ocean. Mermaids first gain the ability to morph their legs into tails once they reach the teenage.

Mermaids can change the color of their scales using the "Change Scale Color" interaction via mirrors. The color of the tail is the same as the color of the scales on their legs while in their human form.

Both genders have their own unique tail flipper. Males have a more classic mermaid style flipper, while females have a more curved and swirly style. Females also have seashell bras, it's color can also be customized with the "Change Scale Color" interaction.

Needs
The color of a Mermaid's needs are blue instead of green, which the normal Sims have, and their needs are not much different than that of normal Sims, except for two differences.

Their hunger need is a little different than that of normal Sims. Mermaids do not get much satisfaction from eating normal meals, thus it doesn't fill up their Hunger as much as it does for normal Sims.

A Mermaid's main food preference is kelp and fish. Fish can be caught from fishing or while scuba diving in diving areas. Mermaids can eat fish raw, and although it seems a tad bit cannibalistic, it does give them a large boost to their hunger need. Vegeterian Mermaids get nauseous from eating fish, so it's advised that they only eat kelp.

Even though fish gives a Mermaid a lot of hunger satisfaction, the primary food preference for a Mermaid is kelp. It can be harvested from diving areas. Eating two pieces of kelp is enough to restore a Mermaid who has a really low hunger need, to full.

It's to be noted, that when a Sim is transformed into a Mermaid, their favorite food will change to kelp. This does not seem to happen to natural born Mermaids when they age into teenagers, who keep the favorite food they were born with.

Another big difference is the fact that Mermaids do not possess the hygiene need, and in it's place they have the hydration need, which is fairly identical to PlantSim's water need.

Hydration works just like hygiene. Mermaids should be constantly kept hydrated, thus requiring frequent swimming sessions either in a pool or in the ocean. Their hydration can also be satisfied by taking showers, baths, or relaxing in a hot tub. If The Sims 3: Seasons is installed, they can also satisfy it by standing in the rain.

Once a Mermaid's hydration need goes too low, they will start to dehydrate and dry out. First they become "Chapped", which is a neutral moodlet, and then they become "Flakey" which is a negative moodlet. Eventually they will pass out, and if another Sim does not splash water on them, the Mermaid will die and become a ghost from dehydration.

Another unique mechanic for Mermaids is their constant requirement for salt water, meaning that they will need constant dips in the ocean, or else they will develop the "Salt Water Deficiency" and then "Adapting to Land" moodlets. If they continue to abstain from swimming in the ocean, they will eventually lose their scales and Mermaid status and become normal Sims.

The Lifetime Reward Permanent Mermaid, which costs 5,000 lifetime happiness points, makes this requirement void. Thus, mermaids can remain on land without having the need to swim in the ocean. This reward is only available to Mermaids.

Abilities
Mermaids have various special abilities and advantages that make them different from normal Sims.

For instance, Mermaids can breathe and stay underwater indefinitely, and will not get the "Depressurising" moodlet when returning to the surface. They also swim much faster than normal Sims, both underwater and above. Once a Mermaid reaches their teenage, 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. Also, Mermaids who have the Evil trait are able to summon sharks to attack other divers.

There are also other small little benefits to being a Mermaid, such as never being attacked by the Kraken, sharks or the underwater monster.

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.
 * Mermaids are unable to get a tan.
 * Just like other life states, Mermaids cannot become another supernatural without having their Mermaid status revoked first.