Why is it risky?
Occasional raw fish isn't acutely toxic, but regular raw fish consumption carries two real risks: thiaminase enzymes in some raw fish break down vitamin B1, and raw fish carries higher bacterial/parasite load than cooked. This is distinct from your existing "Cooked Salmon (Plain)", this one addresses raw specifically.
Affected Systems
Digestive · Nervous
Symptoms
From thiamine deficiency (with chronic feeding): loss of appetite, weight loss, neurological signs, seizures in severe/prolonged cases. From bacterial contamination: vomiting, diarrhea, fever.
What To Do
For occasional ingestion, monitor only. For cats on a regular raw-fish diet showing any of the above signs, consult a vet.
Notes
This is why commercial raw diets use thiamine-supplemented fish, not an argument against raw feeding broadly, worth being precise about that distinction in the article to keep credibility with raw-feeding readers.