Nitrates are virtually harmless to fish. I'm sure they are not the cause of your deaths. Nitrate levels are usually controlled through water changes, however.

Concerning the deaths, we'd need more information. Did you have aeration/water movement? Was there shade? How was the water temperature? Sometimes goldfish will die after water changes because of elevated levels of chlorine and/or chloramines (or other contaminants) in your drinking water supply. Is that what you refilled with?

Did you mean nitrites? Nitrites are toxic, nitrates are not.

How high did your test say the levels of nitrates(or nitrites?) were?

Like others have said.....nitrAtes are harmless, but high nitrItes are deadly. Check and see which one you are testing for. Also test for ammonia, pH and nitrites.

I'll check which one i'm looking at. I thought it said nitrates, but i could be wrong. Water temp was 65, I have a pump with water aeration. They are in the shade & sunlight. When I did water change I added the chlorine rid stuff. I only have access to city water which is very hard, but I always add the starter to get rid of the chlorine.

Wow I am so blind. My test does do Nitrates and the whole 9 yards, but what I was reading was indeed Nitrites. I checked at lunch here about 15 min ago and the NITRITES were between safe-stress. What can i do about this??

If you did a large water change I would suspect the ph may have changed. Get accurate levels for ph, ammo, nitrite and nitrate, not just good or bad. Except for ph, high ammo, nirtites, and nitrate can be lowered by water changes. Nitrites are usually low except when the tank is cycleing.

i just have the test strips that does all the test. It doesn't tell me the amount whether it be high or low. I did order a nitrite kit that would give me numbers though.

I should add that the rest of the fish are just sitting at the bottom. They will come up and eat, but that's it. They were active 4 days ago, but lately they just sit there. I don't want to lose them.