Cloudy tank + black dust like substance on rocks! help! - Tropical Fish Keeping - Aquarium fish care and resources
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post #1 of 5 Old 09-14-2009, 06:59 AM Thread Starter
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Cloudy tank + black dust like substance on rocks! help!

hi guys, im new to this forum..

a couple of days ago, i decided to give my 100g tank a general cleaning..

cleaned the gravel + rocks + filters..

after the cleaning i added 50% water from the tap and 50% water from a cycled aquarium thinking it would cycle the tank quicker..

also, got a filter from my cycled tank and placed it on the newly cleaned tank..

then i put anti chlorine and stressout angel drops..

the following day i introduced some of the fishes from my old tank to the newly cleaned tank, 5 clown loaches, 3 hujetas and 3 pulchras..

everything seemed fine for the first hour, i thot the water was starting to clear up.

5 hours later the tank became really cloudy.

so i did a 25% water change.

the next day, i noticed black stuff on the rocks.. when i tried to wipe it off with my fingers it came off pretty easily as if it was just laying on top of it.. it came off like dust..

i checked my water parameters all seemed to be just fine..

ammonia - 0
nitrate - 0
nitrite - 0
pH - 7.2 (pH that came out of my tap was 6)

someone help me? whats happening to my tank? is the black stuff bad for the fishes?
any help would be great!!

:e vil:: shock::s hock:
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post #2 of 5 Old 09-14-2009, 07:30 AM
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In a mature or (cycled tank)you should have some kind of reading for nitrAtes. The test results indicate that the tank is still maturing, or (cycling). I would not worry about cloudy water during this time for nearly all tanks go through this period during (cycling). It could be a bacterial bloom which is a good thing, and will dissappear within a few days to a week. Best to leave the filters and substrate alone during this time. Is the filter you added from cycled tank the only filter on the new tank? Is it large enough for the new tank? Probably best to run the filter from the cycled tank along with new filter if you aren't already. Bacteria needed will colonize both and they should be left alone until the tank has (cycled).
I am concerned with the large difference in pH from that which is in the tank, to that that comes from the tap. I might run a bucket of tapwater into a bucket and let it set for twelve to twenty four hours and then test the pH of the bucket to see if the pH is closer to your tanks pH. If so, Then I would let water used for water changes set for at least twelve hours before using to avoid sudden change in water chemistry during water changes. I will assume you have had no problems with the other tank or tanks in this regard?
The fuzzy black stuff could be a number of things, from silt, bacteria,algae,residue from substrate that may not have been rinsed enough, or fish waste that may be gathering if filtration is not strong enough. In any event, if fish appear not to be affected, I wouldn't worry until after the tank has matured or (cycled). As you may know,, the beneficial bacteria will gather on all surfaces inside the aquarium and in my view,should not be disturbed during this time. Plenty of time to clean up the tank and decor,after the tank has (cycled).
Do take another pH reading of both your tank and the tapwater. Is possible that something in your tank in the way of substrate and or rocks used for decoration is altering the pH. This could well be problematic in the not so distant future.

The most important medication in your fish medicine cabinet is.. Clean water.
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post #3 of 5 Old 09-14-2009, 08:14 AM Thread Starter
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i havent had any problems with the PH level of the water.. my other tank's ph level is the same as the one in the newly cleaned one...

i think that my fishes lost their appetite since the feeder fish that i left in the tank with them are still there, when usually it would be consumed over night.. its been 2 nights now and the number of feeders in the tank still looks very similar... :<

im starting to worry.. i dont want to loose any of my fishes..

i never had this problem with bacteria bloom before.

i had newly set up filters and with a newly set up tank and never went through this. i would usually put my fishes in the tank after a couple of hours of letting the filters run in the tank..

all fishes would look healthy and active. never had a loss yet..
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post #4 of 5 Old 09-14-2009, 08:38 AM
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Cleaning rocks,gravel,and filter all at once could have upset the biological filter(good bacteria). Filter material should be cleaned with dechlorinated water or old aquarium water. To clean the material with tapwater would kill beneficial bacteria that is found there. Vaccuming the gravel would, or could, kill more. Always best to clean small area of the gravel with gravel vaccum at each water change and a different area each time. That way some bacteria remains active. I would keep a close eye on ammonia readings for the next few days and be prepared to perform a water change or changes to lower ammonia should it begin to rise.
I would also leave the filters alone for the next couple weeks and would reduce feedings. This will help your tank build back up the bacteria that may have been lost during the recent cleaning. You indicate the 100 gal is a new tank ,that you placed a used filter on to help speed the cycle. This is good but stocking with too many fish too soon with no bacteria other than that in the filter,and then cleaning that filter ,and the gravel ,and the decorations all at once, has in my view, caused the tank to stall in the cycling process. I might (would) remove the clown loaches and place them temporarily back into tank that they were in if possible. Removing some fish would help keep possible ammonia spikes from killing these sensitive fish.
I also would not feed feeder fish that I was not raising myself. Many of these cheap feeder fish can and have introduced diseases and parasites to otherwise healthy aquariums.Too many more nutritious prepared foods on the market today to risk it in my view.

The most important medication in your fish medicine cabinet is.. Clean water.

Last edited by 1077; 09-14-2009 at 08:41 AM.
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post #5 of 5 Old 09-14-2009, 01:38 PM
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I thought all this sounded familiar, then realized I had replied to the same questions from you (oznerol) in the BC forum. That's fine, just to say I agree with what 1077 has suggested. We are takling the same thing.


Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
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