Neon tetras turning orange?

[Datreeferman]

Hi everyone, I got 4 neon tetras about 2 weeks ago and looked perfectly healthy but now they look like they're turning orange little by little. My params are good except my nitrate/nitrite are a little hi so I'll do a water change. Any ideas of what it could be, I have 2 other fish, driftwood,plants;fake and real, and sand and gravel.

 

[bainlykin]

Neon tetras are prone to a illness called neon tetra disease. Their color fade slowly and eventually die. As far as I know there is no cure for that. Quarantine sick fishes is to best thing to do.