Freshwater Aquarium/Cloudy water



I hope you may be able to help me.  I have an 85 gallon tank that is currently housing an Oscar about 7 inches, an Oscar about 3-4 inches and a bushy nosed pleco around 4 inches. The tank is cloudy.  I have 3 filters in there, I went to a fish store and bought a bottle of Accurel-F to try and clear it up. The water turned brown for about 3 days, now it is right back to cloudy again.  I tried adding some Pisces Plus water conditioner afterwards when I changed about 20% of the water.  It's still cloudy.  Maybe I'm doing too much at the same time? I've had smaller tanks in the past with clear water and no problems, but maybe since its a little bigger and different type of fish, something is wrong?  When I went to the fish store I took a sample of the water and the guy said the PH was fine, once he put the strip in the water turned blue.  Sorry, but I am at a loss here.  I just want my guys to be happy and healthy!

Hi Dell

Yes, you're doing too much at once. Oscars are very messy fish and need twice the filtration that your tank requires. For example, in an 85 gallon tank, you need a filter for 170 gallons. In my 90 gallon Oscar tank, I have a Fluval 306 canister filter and 2 Penguin 350 Bio-Wheel power filters, one on each end. This gives me 210 gallons of filtration and the water is crystal clear. When you say you have 3 filters in there, are they internal filters? If so, that is one of your problems. Internal filters are useless. I would definitely consider upgrading your filters.

Cloudy water is usually the result of a bacteria bloom caused by excess food and fish waste. As I said before, Oscars are very messy and along with needing additional filters, they need 2 weekly water changes. In my Oscar tank, I do a 30% water change on weekends, then a 15% water change about mid-week.

Chemicals that claim to produce miracles do NOT work! The only way to resolve water quality issues is with water changes. I never add any chemicals to any of my tanks other than water conditioner. So I would not add any more chemicals to the tank.

What I would do in your case is a 50% water change. Then a 10% water change every couple of days until the water is clear. Remember to siphon the gravel thoroughly to remove excess waste. Once the water is clear, I would follow the water change schedule I mentioned above.

Hope this helps you, good luck!


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Richard Hight


I own and maintain several freshwater aquariums from 2 to 180 gallon. I can answer most questions about freshwater aquariums, including setup, cycling, maintenance, compatible tank mates, feeding. Moving? I've moved fish both across town and across the country and can help you get your little aquatic friends to their new home safely. I know and have experience with most freshwater community fish, South American Cichlids and African Cichlids. I don't answer questions about Goldfish or keeping Goldfish with Tropical Fish. I also don't answer questions about keeping crustaceans (shrimp, snails, crabs etc) with Tropical Fish, nor questions about saltwater fish or aquariums. I'm not available to answer questions on weekends, this is when I do maintenance on my own tanks.


Many years of personal experience with community tank fish, semi-aggressive fish (Barbs, Tetras, etc), Angels, South American Cichlids and African Cichlids.

HSG 2010-2011 prof

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