Yes, anal gland secretions smell fishy, its gross!!!
Are you sure it's from the vagina and not the anus? Some dogs have problems with their anal glands, and it can smell pretty bad! It's an easy fix, though, if that's what it is. Your vet can express the liquid for you; and if it happens again in the future, you usually don't even need to see the vet, just the vet tech...kinda like when you bring your dog in to have the claws clipped. Take care!