It could have just scraped your throat
It is possible that the scales injured your throat on their way down.
itself may be producing a foreign body sensation.
There is nothing you can drink or eat that can dissolve it.
Try looking at your throat in the mirror to see if anything is stuck in the throat. If you happen to see it then you should see an ENT specialist
to get it removed.
If you do not see anything then I suggest you wait till morning, If your symptoms get better that means the foreign body sensation was caused by the injury.
If your symptoms get worse or remain same then you need to see a gatroenterologist. You may require an upper GI endoscopy
to look into your food pipe. If the salmon piece is still stuck in your throat then oit can be removed with the endoscope.