PLEASE PLEASE HELP 
Ok suddenly my fish are completley still, not swimming at all and staying there in one spot. Just done a 50% WC as was polluted by potatoe that a flatmate put in there a few days ago.
Just done a test and....
NO3 = 0
NO2 = 0
GH = 16d?
KH = 10d
PH = 7.2
I have a rena panorama 60
Thank u
Ok suddenly my fish are completley still, not swimming at all and staying there in one spot. Just done a 50% WC as was polluted by potatoe that a flatmate put in there a few days ago.
Just done a test and....

NO3 = 0
NO2 = 0
GH = 16d?
KH = 10d
PH = 7.2
I have a rena panorama 60

Thank u