Table of contents

    Version as of 21:23, 15 Aug 2022

    to this version.

    Return to Version archive.

    View current version


    Beneficial bacteria are essentual to fish keeping and the aquarium as they process the toxic biological waste produced by fish.

    The most toxic substance is NH3, free ammonia and this comes from the fish passing urine from there gills.

    There are two main types of beneficial bacteria required for ideal water conditions in a fish tank or pond and they live every where but most prolifically in your filter systems.

    The first type is called nitrosomonas, and these are aerobic bacteria which convert deadly ammonia into another toxic less toxic substance called nitrites. The second type is called nitrobacter, which converts these toxic nitrites into less harmful nitrates.

    With out the bacteria polloution can qucikly build up and kill the fish present.


    In a new aquarium or pond  you can avoid new tank syndrome by slowly cycling or maturing the aquarium.

    This means adding fish stocks are introduced slowly feeding is kept light and monitoring the NH3/NH4 level continously to ensure the fish are kept safe.

    Some people use fishless cycling but this also has some risks such as understanding where the ammonia level is at all times with exahustive test regimes. An alternative is the seneye device.




    In a new fish tank, ammonia must be present to start the nitrosomonas colonies, but the ammonia levels should be just enough to feed the bacteria because excesses will harm the fish. The same is true with the nitrobacter – they proliferate in the presence of nitrites but until there are enough colonies to process the nitrites, excesses will cause distress to the fishes. Therefore, the tank’s ability to sustain more fishes improves as the colonies of beneficial bacteria increase.

    Because the speed of aquarium cycling depends on how quickly bacterial colonies grow, fishkeeping experts suggest several ways to rapidly proliferate bacteria. The most common method is to migrate bacterial colonies from disease-free established aquariums by moving gravel, décor, or filter media to the new tank.

    If migrating established bacterial colonies from existing tanks is not feasible, there is always the “canned bacteria” option. Preserved nitrosomonas and nitrobacter bacteria can be purchased from reputable fish hobby vendors. Some providers claim that their bottled bacteria colonies can jumpstart the cycling process as well as revitalize a failing or overstocked aquarium.