Something in the Water.. Anyone else's pets (birds, fish, etc) suddenly DYING?

I've always trusted NYC tap water yet still let it sit a couple days before water changes. While visiting for a month these holidays, I changed my mom's goldfish that she's had for about 3 years and they are all dropping like flies. Well they had been even before I got here otherwise I'd blame me. Two different tanks, 1 ten gallon and 1 30 gallon.

Even more sadlly she has a young flock of Zebra finches. There were 11 back in December, now only 1 is left alive. They also were around 3 years (the oldest) and being 3 generations, the young ones barely a year, and now died suddenly.In each instance I heard them singing (the males) and chirping (females) all day and then the next, the same ones that seemed so happy were dead stiff. My hunch is the water but we switched to filtered/purified bottled water (DaSani?) after the first one and the fish died last month and still the birds have been dying so maybe its the city air or something? I used to be a vet technician and I see/saw no ill signs at all, just sudden deaths. My mom will be devastated if this last cute little zebra finch hen "survivor" named Molly, croaks too =(

I do hope no one else is dealing with serial loss of pets. Personally I don't believe in keeping any pets other than spayed/neutered mainstream domestic ones but these were somewhat much easier for my mom to care for than a dog or kitties.

Could it be a faulty heating system leaking carbon monoxide or some other poisonous gas?
Finches would certainly be more susceptible than humans to that, not sure about the fish, but if it was the water then why did it still happen when using the filtered/bottled stuff?
strange
GTD

Could it be related to Sandy?

I assume you know Teflon kills birds. They now have Teflon coated light bulbs/stove burner protectors/etc. Dunno about the fish. Maybe they put more chlorine in the water since the disaster. Did the fish turn white or have lesions?

The most common cause for this is chlorine in the water. It is added from time to time to lower the germ levels. In the US there may as well be fluoride, not sure about NYC though. You should call your local water supplier and ask if there have been additives added recently.