Yes, cats can drink tuna water. However, this water should not be a regular part of your cat’s diet. The main reason for this is mercury ingredient in tuna water.
Some tuna might contain ingredients like olive oil, vegetable broth, or soybean oil. Always choose a tuna that’s set in water with limited other ingredients.
Tuna water isn’t particularly healthy for cats, but it’s not dangerous either; actually, it can help increase hydration in cats. Just be careful to give your cat tuna water in moderation.
Mercury poisoning in cats is rare, so, occasional tuna treats are probably safe for them. But, tuna-based foods should definitely not be your cat’s daily treats. A safer option for your cat would be goat milk or bone broth.
A small amount of tuna flavored oil will probably not be harmful for your cat, but, it is better to avoid it. Tuna in oil has high fat content, so, it is likely to upset your cat’s stomach and cause diarrhea.