Why
Raw fish can harbor parasites such as Anisakis and harmful bacteria. Some fish contain an enzyme that destroys vitamin B1 (thiamine), so cats fed raw fish often can develop thiamine deficiency with neurological signs. Dogs that eat raw salmon or trout from the Pacific Northwest can get salmon poisoning disease, which can be fatal. Cooking greatly reduces these risks.
How to give it / if eaten
Steam or bake fish plainly until fully cooked and remove every bone. Keep it under 10% of daily calories and don't let fish replace a complete diet. Sashimi is best avoided, with or without soy sauce or wasabi, because it's raw.
Watch for these signs
Vomiting, diarrhea, poor appetite and lethargy are common. Thiamine deficiency in cats shows as wobbling, a downward-bent neck, dilated pupils and seizures. A stuck bone causes gagging, drooling and pawing at the mouth.
FAQ
Can I give my cat a piece of sashimi?
One piece rarely causes trouble, but we don't recommend it because of parasites and bacteria. The same fish cooked is far safer.
Can my cat eat fish every day?
Fish alone doesn't meet a cat's nutritional needs, and raw fish adds thiamine-deficiency risk. Feed a complete diet and offer cooked fish occasionally.
General information only. Weight, age and health conditions change how a pet reacts, so ask your vet if you are worried.