Echo

[dared]

Revised.

Echo

Laying bare on moonlit water, 
Swaying with gentle breeze. Are you swaying, or is it the water? Because water doesn't sway as much as ripple. On closer revision, it's clear that you are the one swaying. But I think the line itself doesn't make sense if so, it'd be better to say "swaying in the gentle breeze". 
Say, in every shell living a soul? Grammatically incorrect. 
Nay, there's nothing but an echo. The best line.

It's promising, but it's much harder to edit a small poem like this one than a bit lengthier one. You also have a rhyme scheme so it's even harder to edit. Good attempt but it has flaws.