# Help!! Urgent....Black Spots on Gold Fish



## gsb_78 (Feb 15, 2008)

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


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## herefishy (Dec 14, 2006)

I once had a comet that survived for 3 weeks in a "killer" tank that had (2)26" gold clown knives, 20" rtc, a 15" arowanna, and a 3' tiretrack eel. I figured any fish tht could survive that long in that tank deserved to be saved. I pulled him and placed him in his own 20g tank. He developed the same symptoms. I found that he had hook worms. They were not all on the spots, but some were. I am not a goldfish expert, but have read up a little on them. They do morph, in color, as they grow older. This may be what is happening. I would also check for hookworms. You will notice them by looking for a raised scale. They can be removed with a small set of hemostats or may be chemically treated. I prefer the first method.


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