What about them? Nitrite is largely irreverent in salt water, phosphate levels of anything short of fertilizer wouldn't kill a fish and nitrate levels wouldn't directly kill a fish, only shorten it's lifespan and make it susceptible to illness. My sps would die from these long before a fish would.
I did check my nitrate and it was at 3ppm, a little higher than normal but I can attribute it to the dead fish in the tank. The LFS owner told me he keeps his tanks at 1.022 (which is low for such a fish) and I keep my tank at 1.026sg, sora a big change even with acclimation.
The fish was wild caught, it could have been decompressed poorly, sustained stress from shipping, been caught with cyanide and or been exposed to something at the LFS. There is also a chance my CBS killed it, but I don't think so as my goby (who is smaller) is still alive.