You asked for our opinions, not only on the "artistic merits of the piece" but also on what we consider "poetry".
I find even
this (which I find ridiculous) is closer to poetry than the fish presented above.
As for the "percussive berceuse" description, I'd rather hear "real" music in a poem/lullaby than thumping and thming. The mini-essay, though it tries desperately with whimsical arguments, fails to convince me that "Fishces Nachtgesang" is poetry.
It is not music. It is not poetry. It's a drawing of a fish made from macrons and breves.