Will nitrates affect rainbow threadfins?

[guppy12]

I had 5 rainbows in a 20 along with other tankmates... They started to die off and i thought so i put a guard on the back. then finally when i was down to 2... i fianlly tested the water. Everything was prime except the nitrates... it was at 100
I did a 75% water change and now their back to 0...
just wondering if that was it
Everything points to that

G12

 

[CaysE]

100ppm nitrate shouldn't be lethal to the fish. Do you have any live plants? Are ammonia and nitrite readings at zero?

 

[Devilishturtles]

A 75% water change should also get you a reading, however small it may be. What kind of kit are you using?

Threadfins are more sensitive than most rainbow species so a prolonged exposure to 100 ppm nitrates and poor water quality could have resulted in their demise.

 

[guppy12]

Yes every thing was at zero except the nitrates and ph
I do have a lot of live plants

thanks G12