While some fish can be a good source of protein and omega-3 fatty acids, some fish contain high levels of mercury, which can be harmful to a developing fetus. Additionally, some fish can cause allergic reactions in dogs.
Here's what you should do:
* Talk to your vet: They will be able to tell you what type of fish, if any, is safe for your pregnant Jack Russell Terrier to eat.
* Follow their advice: Your vet will advise you on the best diet for your dog based on her individual needs and health status.
Remember, it's always best to err on the side of caution when it comes to the health of your pregnant dog.