# Fish turning black and dying



## Sandi (Oct 9, 2011)

I have a 30 gallon BioCube tank that has been set up about 2 months.

Two of my Mollies and two of my Gouramis and one silver fish have all turned black and died. It starts on the head and works its way down the body and by then they die.

I had my water checked and all levels are within normal limits. Ive done a 40% water change twice. 

I now have one orange Molly and one Tiger Barb that are turning black.

I only have them and 3 neon tetras, one more Tiger Barb and a sucker fish left in my tank.

Please help - what is going on??

Ive had tanks in the past and have never seen this happen.


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## iamgray (Jul 16, 2010)

I know you said parameters are in normal limits, but can you post the actual numbers? Also, what test kit was used? I have never had a fish turn black and die, but I just did a quick google search and found a few other forums where people suggested that turning black is a symptom of ammonia or nitrite burns.


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## Sandi (Oct 9, 2011)

I also have 4 real plants.

I just retested my water and got:

GH - 120
KH - 80
pH - 7.5
NO2 - 0
NO3 - 20


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## ladayen (Jun 21, 2011)

What about ammonia, NH4?


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## trit0n2003 (Nov 2, 2010)

I think it is ammonia burn


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