How many did it killed?
"killed" —> "kill"
tip of the flames reached the sky
I'd recommend adding either a "the" or a "that the" or something akin, the transition feels awkward. Also, "tip" should be plural as it's multiples flames, thus multiple tips.
and the smoke drifting towards Canada.
Two options here: either swap "drifting" for "drifted" or nix the "and".
wood cracks as flame slither upon them like bull kelp
"flame" —> "flames"
Oh, how must that fire have felt like!
Either nix the "like" or change it to "Oh, what that fire must have felt like!"
to have a trunk falls upon
"falls" —> "fall"
as if flame burns within
Either put an "a" before "flame" or make "flame" plural
the water keeps fire sparkled lights upon peaks of the waves
This one is kinda hard to parse. Do you mean "the water keeps the fire's sparkled lights upon the peaks of the waves"? It's a bit weirdly worded.
The feelings are often of cold, of dark, and slow falling of death as everlasting snow within the water column.
Is this the fish relating what their feelings usually are? If so, I'd recommend communicating that a bit better, something akin to "My own feelings are often…" or whatever.
Also, "and slow falling of death" also strikes me as strangely worded.
I heard flames from the others within the ocean.
If this is just about flames in general, then you should throw a "of" in after "heard". If this is specifically about the Oregon fire, as it seems to be, then it needs to be "of the" instead of just "of" since you're addressing a specific thing rather than a general concept.
felt the gravity dragging you down
Nix "the".
Sometimes, I slow down to meet those behind me, and I ask:
'Is the fire in Oregon still burning?'
They said: 'Maybe it stopped, maybe it didn’t. I didn’t check.'
An example of the tense issue I spoke of. The fish stops and asks in the present and they respond in the past, "I ask" and "They said".
nor does those dancing sparks in your mind will ever help you find a mate
I'd swap "does" for "will", nix the later "will", and insert a "to" between "you" and "find".
ever stood together
"stood" —> "stand"
mix into the Orca’s songs
A note to make "Orca" lowercase.
and from that ship, thrown all penetrating spears of the same steel.
Firstly, I'd nix the comma and change "thrown" to "threw".
Secondly, if you're describing the spears as "all penetrating" then it should be "all-penetrating" instead. If not, then I'd nix "all" entirely, leave it to be "threw penetrating spears".
They have lived through that course of history
What course of history? This isn't a request for specification, more a note that you haven't mentioned a specific time, era, or whatever.
stabbed each other, and pushed the bodies into the sea
I'd recommend nixing the comma.
until the water-stained red.
Nix the hyphen between "water" and "stained".
where krill rise up for the algae, and I take a bite of them. The calcium rich krill.
I'd recommend nixing the last sentence and instead making it a part of the description of the krill the first time, i.e. "where calcium-rich krill rise up"
Science theories in human society reach the ocean slowly
I'd also recommend changing "Science" to "Scientific".
As I delve down the water gets darker. It is freezing even to a cold-water fish. I delve through the underwater galaxy of planktons, through the ever-falling ocean snow, until I feel the heated water rising from below. The water smells of sulfur.
Now I stand within the streams up of a hydrothermal vent.
Transparent flames surround. It burns as if my scales are on fire, and the water pushes as if a tree falls onto my body.
I am forced to twitch, to run, waving my fins as if mad, for the transparent flames are surround.
It burns within me as my soul’s ache spills through cracks.
I'd recommend making all of this a connected paragraph. And even if you decide to keep them as their own statements, I'd say you should give them breaks between rather than having each line right below the other as you would regular paragraphs.