The Secret Life of a Mermaid

Amy: I can explain."
Brenna: That's what you always say.

The Secret Life of a Mermaid (or SLM) is a YouTube webshow, created by Christine aka teenie989. Amy Samuels (Christine), a preteen girl constantly in a Sibling Rivalry with her older sister Tess (Bridget) and who loves to swim, the pier being right by her house. One day, however, it begins to thunder while she is in the water, and she takes shelter in a mysterious cave with an equally mysterious waterfall. The next day, she sprouts a tail upon contact with water, and discovers she has some nifty powers to go along with her tail. When wishes for someone to rely on, a girl named Brenna moves nearby, wanting to be Amy's friend. But Amy, wanting to protect her secret, is a bit reluctant to be Brenna's friend, afraid she will find out about Amy's mermaid status and expose her. Inevitably, Brenna plunges into the water in search of a large pink fish she saw, only to end up at the very cave Amy became a mermaid at. When she falls in the shower at Amy's, Amy discovers that Brenna has become a mermaid as well.

The two girls begin to explore their powers, but one day comes when Kelsey, an overachiever who excels at most subjects, comes to work on their science project and becomes jealous that Amy has been spending so much time with Brenna instead of her. When Amy goes running upstairs at her Christmas party, Kelsey follows her only to faint upon seeing Amy with mermaid tail. Plagued by nightmares, she confronts Amy, who reveals her secret, and suspecting Brenna is a mermaid, she pours water on the other girl, to find that she was right. Metaphorical cat out of the metaphorical bag, Brenna and Amy decide to show Kelsey their powers as well. Kelsey, intrigued, wishes to be a mermaid as well, but is disappointed to have Amy and Brenna say otherwise. She makes the two girls a scrapbook, which Amy evidently drops in the water at the pier. Kelsey sets of to find the scrapbook, only to be knocked unconscious and rescued by Amy and Brenna, who pull her up into the cave.

Amy wakes up to find it raining outside despite it never raining that time of the year, and her tail spontaneously appears without touching water. At Brenna's house, it's much too hot and her tail randomly appears as well, now yellow. Kelsey's room is freezing even though the thermostat reads 82 degrees, and she pops her tail for the first time. The three girls meet up at the park, telling each other that their powers aren't working, and later meet up at Brenna's house to discover that they each have a different power. Amy has water (manipulation of water), Brenna has heat (fire, boiling), Kelsey has ice/freezing. One day while swimming, they encounter a girl named Blaire (Tessa) whose mother was a mermaid (the genes skip a generation), and her mother abandoned her and her father to live in the ocean. The girls struggle with keeping the secret at Amy's birthday, discover their tails have disappeared for a day, Brenna has a few seeing Red moments, they find three crystal necklaces and Tess nearly learns the girls' secret.

Amy tells Tess about them being mermaids, thinking it will make Tess trust her after she, Brenna and Kelsey knock her unconscious under the spell of the eclipse. Tess, however, sends information to a marine lab revealing their secret. The girls try to follow her, but are unsuccessful. They later learn that Tess didn't go through with it and has been grounded. One day, stuck inside because of the rain, Kelsey and Brenna begin to turn on Amy. All is well until Blaire returns from Key Largo, not wanting to reveal anything, and Brenna and Kelsey bring to fight. Amy throws herself in between the two of them, and their concern for Amy counteracts their anger for each other and they make up. Amy's cousin Andy comes over, and the girls race to find her and find out what they did the previous day.

Has its own Character and CMOF pages.

Tropes used in The Secret Life of a Mermaid include:

Acting for Two: Christine plays the main character Amy as well as a newscaster. While the newscasts are usually separate from the main show (and may or may not be canon), the three girls watch a newscast about a fire that they think Brenna may have started in In the Wake.
Adults Are Useless: Borders on There Are No Adults. The only adults to appear only appear for a scene or two. So far the only adults have been Amy and Tess' mother, Brenna's mom, Amy's aunt and Blaire's dad. Also, Bridget briefly plays Kelsey's mother in Power Hour, whose only purpose is to comfort Kelsey from a nightmare.
An Ice Person: Amy at first, then later Kelsey.
Attention Deficit Ooh Shiny: Blaire on a regular basis, although the others have their moments of this as well.
Brought Down to Normal: In Scarce Scales the three girls lose their tails briefly.
Cloudcuckoolander: Blaire once again.
Control Freak: Kelsey has shades of this at times.
Dishing Out Dirt: Blaire's mom.
Do-It-Yourself Theme Tune: Christine wrote and recorded one with her cousin, and sings a cover of Swimming by Florence + The Machine.
Floating Water: Amy occasionally does this.
Playing with Fire: Amy could boil water at first, but Brenna receives this power later on. Her power ranges from hot air to literal fire to boiling water.