Hi my latest water test results
Nitrate 0
Nitrite 20
Ammonia. 0.25
High PH 8.0
PH 7.6

I use seachem prime on water changes,should I do 15% water changes once a week to get the ammonia down to zero or more four fish are still flashing ?,I have 5 pearl danios 4 zebra danios and Four Venezuelan black corydoras in a 85 gallen tank,I was giving the four zebra danios as my friend was going to get rid off them so I know I'm a little over stocked,some advice would be appreciated thanks
Peter

You should be always doing at least 25% a week as regular maintenance. If you have ammonia in the water you need to do more, any time it is present. You have said nitrite is 20; do you mean nitrate? If it's nitrate that's OK but if you really have nitrite at that level you need to be changing almost all of the water to get it down to close to 0.

Sorry nitrite and nitrate are both at 0 I'll do a 25% water change on monday Wednesday & friday and test again next sunday nitrate was 20 a week go now 0 thanks for your advice it's really appreciated
Peter