Well, most fish can handle nitrates up to 40 ppm
. But I would try to keep it under that for safety's sake by changing out the water. No more than 10% a week.
Make sure you scoop out any uneaten food in the QT
as any leftovers also contribute to a higher nitrate level.
, I never did water changes in my QT
tank. I never tested for nitrate either. If I did, perhaps I would have done a change or two.