@Background Pony #1854  
Thanks for pointing it out.

@DragonBoi471  
@Ereiam
 
Actually, based on the creator’s own notes left in the comments section, “unicorn-based” mermaids like Twilight and Rarity, although they do have gills, as long as they can keep them hydrated, like say with a “sprayer or wet scarf (quoted straight from the comment source),” they could stay on land indefinitely, which I postulate is due to the fact I think they have a hybrid pulmonary system, meaning they’ve retained something like lungs for surface use. The only thing then would just be becoming ambulatory out of water, which could easily enough be done with a simple wheelchair. He also hinted that later on Twilight and Rarity could start using their angler horns much like their pony-counterparts’ unicorn horns once they unlock the knowledge to do so, but for now, they’re just decorative and luminous.
 
Rainbow Dash, and possibly Fluttershy in the future, might actually have trouble with surface living, as given the notes, “pegasi-based” mermaids gills’ dry out at nothing, as well as their skin, as they seem to dry out much faster than their unicorn-type counterparts, having a result much like what would happen to a beached dolphin or whale. In trade though, they’re the fastest of all the three types and can make incredible leaps out of the surface.
 
Pinkie and AJ don’t even have gills, which is by design, as was stated that “earth pony-based” mermaids lack gills, opting for something like a “superlung,” meaning they’re more like marine mammals like dolphins and whales, needing to surface on occasion for a fresh breath of air, and unlike pegasi-types, also don’t dry out, meaning right away outside of mobility issues they can resume their terrestrial lives just fine, though he did comment on the idea of them, unlike the other two types, being able to regain their legs once sufficiently dry much like the mermaids of “Splash,” but lose them again if they get wet.
 
If you want the see the original post, it’s in the comments section of the part right after RD has finished changing, the pic’s title being “Pinkie Pie, Agent of that world.”

@Blissey1  
Twilight and Dash develop their gills in >>1035065 and have to dive immediately afterward.

@DragonBoi471  
just because they gained gills doesn’t mean they can’t still breathe air normally.

@Background Pony #A652  
Well, the thing is mermaids have gills (In case you haven’t noticed in any of this artist’s pics) and anything that has gills won’t survive on dry land for too long.
 
If anything, a mermaid would suffocate long before she could reach a laptop :P

@DragonBoi471  
Who says you’d HAVE to live underwater? With wheelchair accessibility being the law in many countries and the increasing ease one can order things online, a mermaid could easily make a go at living in a fourth story SoHo flat, or whatnot.

Shoo-be-doo! Shoo-shoo-be-do!

TWILIGHT, save her!!!

Don’t. You. Dare, Rarity.
 
P.S: the next time I see a mermaid try to come towards me, I’m gonna blow her brains out; I’d rather not have one touch me and force me to live the rest of my life underwater.