I have observed during last 10 days that of the 2 gold fishes i have in my 200 gallon tank, one has developed black spots on its belly and moreover its fins-ends have turned black. Worse news is that it is only increasing each day.
The tank was set up in June'07 & has undergone cycling. I do weekly water changes and vacuuming.But despite that the Nitrate levels reach high levels (25mg/L). Each week i find that dark brown algae starts to grow on the gravel, plants and even on walls of the aqrm(Photo attached).
The fish retailer tells me i need to change water and do vacuuming once a month, but in my case even though i go for weekly water changes(sometimes once every 4-5 days) still nitrate levels reach rock high((25mg/L).
Kindly advise & help!!!.
Currently my readings are:
PH: 7.5
Ammonia : 0 mg/L
Nitrite : <0.3 mg/L
Nitrate : 25 mg/L
The tank was set up in June'07 & has undergone cycling. I do weekly water changes and vacuuming.But despite that the Nitrate levels reach high levels (25mg/L). Each week i find that dark brown algae starts to grow on the gravel, plants and even on walls of the aqrm(Photo attached).
The fish retailer tells me i need to change water and do vacuuming once a month, but in my case even though i go for weekly water changes(sometimes once every 4-5 days) still nitrate levels reach rock high((25mg/L).
Kindly advise & help!!!.
Currently my readings are:
PH: 7.5
Ammonia : 0 mg/L
Nitrite : <0.3 mg/L
Nitrate : 25 mg/L