One thing that I often find odd and strangely consistent throughout most mermaid shows is the lack of parental involvement. I'm not just talking about keeping your tail a secret from them, either. Why does no one have parents that intervene when they dash out the door for an impromptu swim session? How about when they invite someone they barely know over for a full moon sleepover? This doesn't only apply to parents in the strict sense. Aunts, uncles, grandparents, older siblings and more would realistically set up boundaries for any child they were responsible for. I know a lot of shows don't feel like including any actual adults is a possibility, and I applaud those that do involve the older people in their lives. These shows often feel more realistic and fleshed out. Not everyone is young and female.
With that said, let me explain why I feel like having more adults with familiar roles can be beneficial to your mermaid-y piece of fiction.
Tension- Perhaps a character had a very close relationship with their parents (or sibling, grandparent etc.). Their home life would suffer if they ran off with their new pod or avoided family functions. Your family has a way of holding you accountable for your actions. A well behaved child could suddenly be viewed as rude if they ran off frequently to dry off, slam doors, shut people out, and battle sirens in the forbidden forest (I'm in an alliterative mood. Can't you tell?) Tensions would also rise if a characters grades slipped because of their change in species. This also counts if a character's caregivers caught them in a full moon frenzy. Can you say "Awkward."?
Boundaries- This especially applies to younger mers. I can't go from the kitchen to the living room without my parents asking where I'm going and why. I doubt that a character that hasn't finished Elementary School yet is allowed to go wherever they please. Maybe a character's mom wants to chauffer them to their swimming spot of choice and supervise them once they arrive. Keeping a new body part secret from your parents doesn't sound so smart now, does it?
That brings me to an option that is almost nonexistent in practice, yet incredibly logical in theory.
TELL YOUR PARENTS. DON'T TELL THE NEW KID IN TOWN, YOUR DOG, OR SCHOOL JANITOR NAMED KEN THER CRUSHER. TELL THE PEOPLE WHO HOUSE YOU!
I mean your characters should tell their own fictional parents. They shouldn't have to cross universes to tell your parents. I mean, they could if they wanted to. That would be an interesting storyline, most definitely.
Telling parents is a natural move for younger characters or characters that are close to their families. You wouldn't keep any other medical revelation from the people you care about most. Why would this be any different? This might not be a big deal if your characters are off at college or estranged from their family, but that isn't usually the case. Even if you decide against full on coming out to parents, little things like showing your own torso Tom and Jerry style with dialogue meant to come from the mermaid's parent or guardian shows thought and realism.
I might finish this later, or it might be finished. Yay for five page essay style mermaid ramblings!
I need sleep.
Goodnight, Misque