With some reinforcement to make it tougher, yes. One lower and one higher key for each hand. Beginners should start with a 10-key. One per finger, you see?

Yeah, but he's confident he can figure the 14-keyed one fairly quickly once someone shows him how, probably.

He is currently talking to the right mermaid to get a music lesson. For free even, because merfolk culture expects you to teach whoever is interested.

Oh, cool! Yes he'd like to learn how to play this instrument please.

She is happy to demonstrate, then guide him though using it himself. You have to be moving a bit to get it to play, but then pressing the keys lets water flow through just the right way to make sound. What sounds are produced vary a lot with speed, and while both sides are identical making slow banking turns lets the streamers on one side play at a lower pitch than the ones on the other for a nice bi-tone effect.

Like this?

Good first try!

Make sure to do this and such......

He imitates her precisely.

And he's soon pretty good at playing this, especially for a split-tail.

Please forget she said that sorry sorry sorry.

He laughs. "That's a cute nickname. Accurate, too. I wonder..." He unceremoniously strips and sits on the ground to start morphing his legs together into something that at least outwardly resembles a mer tail.

"...Oh, cool. Shapeshifting is whatever you are's magic, huh?"

She inspects the tail. "We didn't expect something like that." We, presumably, because this language doesn't actually have a word for 'I'.

"It's a bit more complicated than that. Where we're from, some van-kires and humans have individual powers like this. Ours is shapeshifting, other people have other powers or none at all."

"Individual magic. That barely makes any sense. At least it makes figuring out your niche easier probably?"

"We didn't design the system," he shrugs. "And magic's secret where I'm from, although it's slowly being revealed to the general populace. There isn't a niche for shapeshifters."

"How do they manage to keep magic a secret? We'd think it's used for so much that it would be obvious. If it's individual though..."

"Yeah, our world is very low-magic compared to yours. Oh, we don't think we mentioned, we're from a different world. Without tiles, just a giant sphere."

"Oh, now you're just lying through your gills."

"We're not! But we don't really have a way to prove it.—oh wait we totally do." He puts a hand on his thigh and shifts the key out of it, then uses it to open a door. When he pulls it, no water falls through it, even though the other side's a huge fall down onto a wasteland.

"Um. Please close that. Right now."

He does, and locks it again, making it disappear. "Sorry."

She shivers. "It looked like a rift."

"—oh, we're sorry, we didn't realise. It's probably safe? And not a rift. Something else, from my world."

"Don't do it again. At least not in our home. We should go back to music, music is fun."

"Right-oh, music is fun."

She teaches him a pair-song with the water-trailing-piano thing, whose proper name transliterates close to 'slelk'il'.