Setup new tank reduced nitrates quickly

[Shinte122305]

So i moved to a new house and moved my fish only tank to the new house. i had two tanks an 80 and a 200 i put all the fish in the 200 i only moved about 25% of the water the rest is brand new water. nitrates went from 25 to 0 and like a few weeks later one fish died out of nowhere (anthias) i cant think of what it could be. same rock that's 2 years old. 0 ammonia 0 nitrite 0 nitrate.

could it be nitrate shock or something.

 

[rkpetersen]

Moves can be stressful. Or you might have a pathogen that's somehow reactivated.
Pretty sure your nitrate level doesn't have anything to do with it.

 

[Thaxxx]

If you didn't notice any symptoms of anything, it's never going to be possible to know. Three weeks in new tank all is fine, to dead, it's a tough call.

 

[Shinte122305]

Yeah all the other fish are fine and one randomly died thats been with me for over 3 years now. only new thing is the move that happened 3 weeks ago