bacteriaThe colonization of beneficial bacteria is absolutely essential to cycling and maintaining an aquarium. These bacteria colonize on surfaces like filter media and within the substrate of your aquarium. However, beneficial bacteria are maintained via a delicate balance and that can be disrupted by things like replacing filters or filter media or overdoing it on a tank cleaning. Not to mention how long it can take to colonize bacteria in the first place for a new aquarium.

Sometimes, we need a little boost to start the bacteria colonization or bring it back after a cycle crash. That’s where bacteria supplements for aquariums come in handy. These reviews of the 5 best aquarium bacteria supplements are intended to help you navigate this seemingly complex world of aquarium bacteria and help make things make sense. Colonizing and supporting beneficial bacteria in your aquarium isn’t as intimidating as it might seem!divider1- goldfish

A Quick Comparison of Our Favorites

Image Product Details
Best Overall
Winner
MarineLand Bio-Spira Freshwater Bacteria MarineLand Bio-Spira Freshwater Bacteria
  • Prevent new tank syndrome
  • Neutralizing ammonia and nitrites
  • Begins and maintains colonization of beneficial bacteria
  • Best Value
    Second place
    Seachem Stability Fish Tank Stabilizer Seachem Stability Fish Tank Stabilizer
  • Best value
  • Cannot be overdosed
  • Contains three types of bacteria
  • Premium Choice
    Third place
    Aqueon Pure Bacteria Supplement Aqueon Pure Bacteria Supplement
  • Cannot be overdosed
  • Mess-free and easy to dose
  • Available in multiple sizes
  • API Quick Start Nitrifying Bacteria API Quick Start Nitrifying Bacteria
  • Easy to acquire
  • Works to reduce toxic waste products
  • Reduces the risk of fish loss during fish-in cycling
  • Fluval Biological Enhancer Fluval Biological Enhancer
  • Available in five bottle sizes
  • Works to reduce toxic waste products
  • Reduces risk of fish loss during fish-in cycling
  • The 5 Best Aquarium Bacteria Supplements – Reviews 2021

    1. MarineLand Bio-Spira Freshwater Bacteria – Best Overall1MarineLand Bio-Spira Freshwater Bacteria

     

    The MarineLand Bio-Spira Freshwater Bacteria is the best overall aquarium bacteria supplement. This product doesn’t just cycle new tanks but also helps clean tanks as well. This is available in an 8.45oz pouch.

    This bacteria supplement contains nitrifying bacteria that help consume ammonia and nitrites within your tank. This immediately starts working to neutralize ammonia and nitrites within your tank. Secondary bacteria in this supplement help clean your tank by consuming sludge and other physical waste. You can use this to decrease the chance of new tank syndrome from occurring, but you can also use it monthly to maintain your bacteria colonies and help improve the cleanliness of your tank.

    This product will create cloudiness in your water when it’s first poured in, but this does clear up within a few minutes. This product is intended for freshwater only.

    Pros
    • Immediately starts neutralizing ammonia and nitrites
    • Works to prevent new tank syndrome
    • Begins and maintains colonization of beneficial bacteria
    • Secondary bacteria reduce sludge and helps keep your tank clean
    • Can be used monthly for maintenance and cleaning
    Cons
    • May cause water cloudiness briefly
    • Not safe for saltwater use

    2. Seachem Stability Fish Tank Stabilizer – Best Value2Seachem Stability Fish Tank Stabilizer

     

    The best aquarium bacteria supplement for the money is the Seachem Stability Fish Tank Stabilizer. This product is available in an 8.5-ounce bottle.

    This bacteria supplement can be used in freshwater and saltwater tanks and can help prevent new tank syndrome. This product contains aerobic, anaerobic, and facultative bacteria that work to consume waste products like ammonia, nitrates, and nitrate. Since these bacteria all survive in different ways, if something occurs that kills one of them off, like the use of a medication, it shouldn’t eliminate all the bacterial colonies. It cannot be overdosed.

    This product needs to be used daily for 7 days during tank cycling to be fully effective, but your tank is not guaranteed to be fully cycled within that 7-day period and this product may need to be used longer.

    Pros
    • Best value
    • Can be used in freshwater and saltwater tanks
    • Contains three types of bacteria
    • Works to prevent new tank syndrome
    • Cannot be overdosed
    Cons
    • Needs to be used for a full 7 days for efficacy
    • May need to be used longer than 7 days depending on the tank

    3. Aqueon Pure Bacteria Supplement – Premium Choice3Aqueon Pure Bacteria Supplement

     

    For a premium aquarium bacteria supplement, Aqueon Pure Bacteria Supplement is the way to go. This product contains bacteria inside of gel balls, making it the easiest product on the list to dose. There are multiple pack sizes available up to 24 balls.

    This bacteria supplement requires nothing more than dropping the balls into the water to begin working, no measuring needed. It can be purchased in 10-gallon and 30-gallon sizes, where one ball is enough for a tank of that size. It cannot be overdosed and immediately begins working to reduce ammonia and nitrites. It also will help maintain clear water in your aquarium.

    This product is intended only for freshwater tanks. It is recommended to be used on a weekly basis and a double dose is recommended per week while cycling a new tank. These balls break down slowly and may stay in the bottom of your tank, even after the bacteria has been released, and need to be removed.

    Pros
    • Mess-free and easy to dose
    • Available in multiple sizes
    • Cannot be overdosed
    • Immediately begins working to reduce waste products
    • Helps maintain clear water
    Cons
    • Only for freshwater tanks
    • Recommended to use weekly for established tanks or double dose weekly for new tanks
    • Break down slowly and may need to be removed from the tank after a couple of weeks

    4. API Quick Start Nitrifying Bacteria4API Quick Start Nitrifying Bacteria

     

    The API Quick Start Nitrifying Bacteria supplement is one of the easiest products on this list to acquire since it is sold online and, in most fish and pet stores. It is available in 4-, 8-, 16-, and 32-ounce bottles and has a freshwater and saltwater version.

    This bacteria supplement works to reduce toxic waste products, like nitrites and ammonia. It can be used during new tank cycling, water changes, when adding new fish, and after a cycle crash. When used as directed, this product will reduce the risk of fish loss during fish-in tank cycling.

    This product does need to continue being used to maintain the bacteria colonies. It’s important to understand that the bacteria in this product require ammonia to feed on, so if there is not an ammonia presence in the tank then they will die.

    Pros
    • Easy to acquire
    • Available in four sizes and freshwater and saltwater versions
    • Works to reduce toxic waste products
    • Reduces the risk of fish loss during fish-in cycling
    Cons
    • Needs to continue being used to maintain bacteria colonies
    • Need ammonia in the tank for this product to be effective
    • Freshwater and saltwater versions are not interchangeable

    5. Fluval Biological Enhancer5Fluval Biological Enhancer for Aquariums

     

    The Fluval Biological Enhancer is available in five sizes from 1 ounce to 0.5 gallons. It can be used in freshwater and saltwater aquariums.

    This bacteria supplement helps reduce the risk of fish loss when cycling an aquarium by inoculating the aquarium with beneficial bacteria. These bacteria will work to eliminate ammonia and nitrites within your aquarium. This supplement can be used during cycling of new aquariums, filter changes, after a cycle crash, and after water changes. The bacteria in this product will, with continued use, prevent the growth of bad bacteria within your tank.

    This product does have to be used routinely for maximum effect and it does need ammonia in the tank for the bacteria to become established. This product instructs daily use for three days for setting up a tank but the tank likely will not be fully cycled within three days, so water parameters need to be closely monitored.

    Pros
    • Available in five bottle sizes
    • Can be used in freshwater and saltwater aquariums
    • Reduces risk of fish loss during fish-in cycling
    • Works to reduce toxic waste products
    Cons
    • Needs to continue being used to maintain bacteria colonies
    • Need ammonia in the tank for this product to be effective
    • Tank will likely not be cycled after three days

    Buyer’s Guide

    Considerations When Choosing an Aquarium Bacteria Supplement:

    • Freshwater or Saltwater: While some products can crossover between freshwater and saltwater, most freshwater bacteria cannot survive in saltwater and most saltwater bacteria cannot survive in freshwater. Make sure that the product you are purchasing can be used with the type of aquarium you have.
    • Your Goal: What are you trying to accomplish with a bacteria supplement? Some products will help with tank cycling and re-establishing bacteria colonies after a crash while others will help keep your tank clean by introducing bacteria that will break down physical waste. Choosing a product that is labeled for your goal will ensure you get a product that will work for you.
    • Your Current Parameters: Check your water parameters before adding any products. If your tank already has high ammonia and nitrites, then you may need to add additional products to help establish the tank. Bacteria supplements are a tool, but they are not a complete solution to tank problems.
    • Check the Date: It might sound like common sense, but make sure to check the expiration date on bacteria supplements you use in your tank. Once they are out of date, some or all of the bacteria will have died, and the supplement will no longer be effective. It’s also important to check the shelf life of the product. Most bacteria supplements for aquariums do not require refrigeration but they are usually only good for around 6 months after opening. Tracking when you open bacteria supplements will help you know if the product is still going to be effective.
    What You Need to Know About the Nitrogen Cycle:
    • What’s the goal? When it comes to establishing an aquarium, your goal should be no ammonia, no nitrites, and nitrate less than 20ppm. If your aquarium has no ammonia but also no nitrates, then it likely is not completely cycled. Nitrates are a byproduct of the breakdown of ammonia and nitrites and can be used by plants for nourishment.
    • How do you accomplish the goal? When it comes to establishing an aquarium, you need ammonia. It may sound counterintuitive since your end goal is to eliminate ammonia, but beneficial bacteria feed on ammonia. In a tank with fish, the ammonia comes from the waste excreted by the fish. In a tank with no fish or invertebrates, there is no source of ammonia. To help establish the bacteria, you need to provide an ammonia source for it to feed on. This can be accomplished via “ghost feeding”, which involves dropping fish food flakes into the tank every day, leading to ammonia production from the decay of the food.
    • How do you know when your tank is cycled? Once you are no longer seeing ammonia or nitrite readings when you check water parameters, but you have a low level of nitrates, then your tank is likely fully cycled.
    • How do you maintain the cycle? Aquariums require routine cleaning and maintenance to ensure the tank stays balanced. Beneficial bacteria colonize in high surface area places with some water flow. The more available surface area, the more bacteria can grow. Changing out filter media with non-established media can cause a tank cycle crash by removing the source of the beneficial bacteria. If you need to change your filter media for any reason, it’s best to change it out a little at a time. Filter media, like ceramic rings and bio balls, do not need to be changed out very often and only require an occasional rinse in dirty tank water to knock off built-up waste. Keeping at least two types of filter media in your filter at all times will ensure you can replace one type of media while the other maintains its bacteria balance.
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    Conclusion

    The best overall aquarium bacteria supplement MarineLand Bio-Spira Freshwater Bacteria for its efficacy and affordability, while the best value product is the Seachem Stability Fish Tank Stabilizer because of its high-quality at a cost-effective price. The premium choice for aquarium bacteria supplements is the Aqueon Pure Bacteria Supplement because it’s effective but not as cost-effective as most other bacteria supplements.

    It’s important to closely monitor your water parameters during tank cycling and routinely with aquarium cleaning and maintenance. These products are excellent additions to a tank, but they cannot fully replace cycling a tank. The bacteria will not survive without a food source and without beneficial bacteria, dangerous waste products will build up in the water, risking the lives of your fish.

    These product reviews are intended to help guide you in choosing a product to better the health of your tank, but it is important to keep a close eye on your fish and water parameters whether your tank is established or brand new.


    Featured image credit: Moto “Club4AG” Miwa, Flickr