The old South Boston Aquarium standsin a Sahara of snow now. Its broken windows are boarded (1–2)
The change is pretty straightforward here: the aquarium from long ago has been shut down and boarded up. Move on; nothin' to see here.
The bronze weathervane cod has lost half its scales.The airy tanks are dry (3–4)
Again, the transformation is one of degeneration. The old place is falling apart and desolate. Maybe it would be a good spot to film a horror flick?
Once my nose crawled like a snail on the glass;my hand tingled (5–6)
These lines set us up for a change that's about to come. "Once" is what tips us off so that we expect a "now" moment. Lowell's got us on the edge of our seat. Who's got the popcorn?