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Results 1 to 7 of 7
  1. Default Regular water changes yet extremely high nitrates

    0 Not allowed!
    Hi all, some help please...

    I have a 20 litre tank, two common goldfish, a waterpump/filter sytem, three pumice rocks (covered in algae) and a live plant going for the past six months, and I do 25% water changes once a week, adding safewater, and feed them a pinch of goldfish flake food twice a day.

    I noticed that the bigger stronger goldish had clamped fins, and was occasionally swimming fast, skittishly, twisting and turning.

    I did a test and the PH, ammonia and nitrites are fine, but the nitrate was at 250 mg per litre, way above reccomended levels, and the general hardness 125 mg per litre.

    I've obviously done an immediate water change, and will continue to monitor to make sure they fall.

    I try and follow good tank maintenance procedures, so my question is how did I get such high nitrates?

    I tested my tap water, and the nitrate levels are at 0.
    They don't have any poo-trails, so I don't think I'm overfeeding them.

    It's very hot where I live right now, and the temperature in the tank reached 85F, which is way above the recommended level for goldfish. (Although the water out of my tap is 71F, which is the top of the reccomended levels for goldfish, so it's hard to bring the temperature down!) Could high water temperature contribute to high nitrates?

    I also don't vacuum the gravel (I read somewhere that good bacteria developes below the gravel surface and shouldn't be disturbed). But should I instead be disturbing the gravel regularly to help get rid of the junk through the filter system - would this help reduce the high nitrates?

    Any advice much appreciated. I don't want to be abusing my fish!


  2. Default

    0 Not allowed!
    You are overstocked a lot. 50% water change twice a week along with gravel vaccing twice a week would help but your conditions will always be bad until you geta a bare minimum of a 30 gal tank for them with an appropriate size filter. The water temps really need to stay under80 with 75 f being better.

  3. Default

    0 Not allowed!
    +1 with Smaug - a 20L tank is waaaay too small for 2 goldfish considering their waste output (hence the need to vacuum gravel - your filter won't get that) and how large they will get. Goldfish also need really good filtration - like for at least double the tank they're in.

  4. #4


    0 Not allowed!
    And here's your answer:

    "I have a 20 litre tank, two common goldfish"

    Are you aware that common goldfish get to be a foot long? Please read those big black letters in my signature.

  5. #5


    0 Not allowed!
    I agree with everyone above. Common goldfish get huge and have a very very large bio load. The fish are looking clamped likely because they are running out of space.

    Here in a nutshell is what goldfish need: LOTS of space, LOTS of filtration, LOTS of meticulous tank cleaning, LOTS of aeration.

    I do realize, the mistakes you are making are mistakes, and that previously you may have been mislead and ill informed on how to keep goldfish, and I myself have made the same mistakes. It is clear you care about your fish, or you would not have sought help. Do read Lady Hobbs information about Goldfish, it is a real eye opener to many of us who thought a feeder fish could live in ten gallons!

    Now, lets see if I can help.

    First. Plan on getting a bigger tank, or, giving the fish either back to the store or to a friend who has a larger tank. The Myth that goldfish only grow to the size of the tank they are in, is in fact, a MYTH. They will grow to fill the tank they are in, and then suffer miserable lives for it. Do your best to gain a proper home for them.

    Second, Clean that gravel! Whoever told you to never clean the gravel in my humble opinion, should be strangled. Gravel is a collection plate of waste products, old fish food, fish poo, and anything else you can think of. THIS is the stuff you need to get rid of. Gravel vacuuming will NOT remove beneficial bacteria that grow on the gravel itself, only take out the impacted detritus. You will be amazed on your first gravel vacuuming that the water comes up BLACK..... and it will answer pretty quickly the cause of your high nitrates.

    Third, treat a ten gallon goldfish tank as a glorified goldfish bowl, and change 50 percent of the water at least twice a week. Goldfish use up available goodness in the water faster than you can blink, so it has to be replaced on a regular basis. Also with their large bio load, a ten gallon is not enough water to disperse their waste products. Your buddies clamped fins are a sure sign of very very poor water conditions.

    Fourth, Get an aerator. An air pump and air stone, the more the better. Goldfish have huge oxygen requirements, and your filter will simply not provide enough. If at all possible, get an air bar, that goes the length of the entire back of the tank.

    Fifth, get that temperature down! Ways to do it is get a table fan and point it directly at the tank. Also, if the tank has a plastic hood, replace it with a screen top used for reptiles. The screen top will also help in the meantime keep a larger surface area for air exchange, and for the heat to dissipate out of the tank.

    Sixth, Rinse the filter media out in the tank water removed from a water change, EVERY time you change the water.

    These are only temporary measures to ease the suffering of your fish, however, a ten gallon will not keep them for any long duration, no matter how good the circumstances. Do everything you can to either re-home them, or get them a bigger home.

  6. Default

    0 Not allowed!
    a 20l is a 5 gal Tiari

  7. #7


    0 Not allowed!
    Quote Originally Posted by smaug
    a 20l is a 5 gal Tiari
    OMG! Holy samolians! Sorry I totally misread that!!! I need new glasses!!

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