Celestrial Pearl Danios

Seriously Fish gives their preferred pH range as up to 7.5 while FishBase doesn't give anything. But SF does give a hardness range up to 268 ppm, which converts to 15 german degrees. This is hard, which usually goes together with pH as high as yours. Since hardness is more important than pH, unless you have extremely hard water, your cpds should be OK.


However, I need to ask, that 8.2 pH - is that the tank pH or the tap pH? And if it's the tap, is that freshly run water? pH straight from the tap is often different from water that has stood for 24 hours - and tank water has stood for longer than that.

That's fine. I just needed to check it wasn't freshly run tap water and then you discover the tank is different.

I'm sure they'll be fine, but if the worst were to happen then you may want to consider Emerald Dwarf Rasbora (Danio erythromicron) as they're well suited to higher pH and harder water. Similar size to CPD's, but seem to be very skittish. Don't keep the two together though as they may hybridise.