Cycling an aquarium is an extremely important part of any tank setup. Proper cycling will prevent your fish from having to be in a tank which displays new tank syndrome, during which nitrite levels spike. 

However cycling a new aquarium can take a good couple of weeks. You need to wait for beneficial nitrifying and denitrifying bacteria to colonize the biological filtration media and the substrate. However using a best aquarium bacteria supplement can help to speed this process along. 

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Seachem Stability Fish Tank Stabilizer - For Freshwater and Marine Aquariums 500 ml
  • TANK STABILIZATION: Seachem Stability will rapidly and safely establish the aquarium biofilter in freshwater and marine systems, thereby preventing the #1 cause of fish death: "new tank syndrome".
  • TREATMENT: Stability is formulated specifically for the aquarium and contains a synergistic blend of aerobic, anaerobic, and facultative bacteria which facilitate the breakdown of waste organics, ammonia, nitrite, and nitrate.
  • BACTERIA GROWTH: The necessary conditions for the growth of Stability's bacteria strains encompass a very broad range. When other bacteria begin to die off (usually from high organic loads caused by the unknown death of an organism), Stability simply becomes more effective.
  • USE: Shake Seachem Stability well before use and turn off UV/ozone filter. Use 1 capful (5 mL) for each 40 L (10 US gallons) on the first day with a new aquarium. Then use 1 capful for each 80 L (20 US gallons) daily for 7 days. Fish and other aquatic species may be introduced at any time as long as dosage is maintained for 7 days.
  • SAFE: The bacteria employed by Stability are non-sulfur fixing and will not produce toxic hydrogen sulfide. Stability is completely harmless to all aquatic organisms as well as aquatic plants, thus there is no danger of overuse.
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API QUICK START Nitrifying Aquarium Bacteria, Allows Instant Addition of Fish and Maintains Active Biological Filter, 16-Ounce Bottle
  • Contains one (1) API QUICK START Freshwater and Saltwater Aquarium Nitrifying Bacteria 16-Ounce Bottle
  • Allows instant addition of fish when starting a new aquarium
  • Reduces compounds harmful to fish when used routinely
  • Helps prevent fish loss in freshwater and saltwater aquariums
  • Use when starting a new aquarium, when adding new fish and when changing water and filter media
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Nutrafin Cycle Biological Filter Supplement, 16.9-Ounce
  • Fast-acting responsive ammonia and nitrite elimination
  • Consistent performance from each container due to bio-floc technology for improved shelf life and product viability
  • Ensures that biological pollutants produced by fish are rapidly converted to a non-harmful compound
  • Helps prevent fish loss
  • Suitable for freshwater and saltwater aquariums

What Are Aquarium Bacteria Supplements?

An aquarium bacteria supplement is pretty much exactly what it sounds like. It is a product which puts beneficial bacteria into your fish tank. 

If you have read our article on the aquarium nitrogen cycle then you will be well aware of the role that bacteria play in an aquarium system.

Without healthy bacteria colonization in the tank there will be minimal nitrification and denitrification occurring. Nitrification is the process through which ammonia is converted into nitrite, and nitrite is converted to nitrate. Denitrification is the process through which nitrate is converted to harmless atmospheric nitrogen.

As organic matter such as fish feces and waste food decomposes ammonia is released. Ammonia is highly toxic to fish, even in small concentrations. Without the nitrifying bacteria converting it into much less harmful nitrate then your tank will quickly find itself in dire straights, with ammonia levels building. 

This is where aquarium bacteria supplements come into play. They place this useful beneficial bacteria into the water column, where it will settle and colonize the biological filter, mechanical filter, the substrate, and anywhere else it will find!

When Should You Use a Best Aquarium Bacteria Supplement?

There are a number of occasions that you should definitely use an aquarium bacteria supplement.

When cycling a new tank

When you first set up a fish tank, it takes a number of weeks to properly cycle the tank. Cycling the tank involves letting the tank run through new tank syndrome, during which first ammonia levels spike, then nitrite levels spike. As bacteria colonize the biological filter the ammonia and nitrite levels will reduce to zero, and the nitrate levels will also stabilize. 

This process can take up to a month or so. However if you use one of these best aquarium bacteria supplements, then you will find the cycling process is sped up greatly.

After medicating fish

If you have had a bacterial disease outbreak in your fish tank, such as mouth fungus, then you will be needing to treat this with antibiotics and other treatments available. 

While treating your sick fish is necessary, and vital for their health, it can have knock on effects. Antibiotics will happily kill any bacteria they come into contact with, and unfortunately this includes the beneficial bacteria found in your filter and substrate. 

This is why it is recommended that you put the sick fish into a separate isolation tank, or at least remove the filter. Not only will the chemical filter remove the treatment, the treatment will kill the good bacteria housed there. 

After medicating your tank, if you then reinstall the aquarium filter you should then add some aquarium bacteria supplement. If any bacteria in the filter have died it will help to reinstate this, and it will aid in the bacteria recolonizing the substrate.

After cleaning

Another time you should use an aquarium bacteria supplement is after you have cleaned the filter. Due to the risk of removing too much of the bacterial colonies, you should only replace a maximum of a third of the biological and mechanical media at once, and only use tank water to clean the rest. Even just doing this can cause a significant reduction in the number of nitrifying and denitrifying bacteria present in the aquarium filter

Using an aquarium bacteria supplement after a filter cleaning will quickly replace the bacteria that have been removed during the cleaning. It is always a risk that ammonia, nitrite, and nitrate levels will spike after cleaning the filter; using a bacteria supplement will greatly reduce the time it takes for the bacteria to get back to full numbers, reducing the risk of ammonia and nitrite spikes.

Also using a bacteria supplement after a water change can aid in preventing the new water from harming existing bacterial colonies in the filter and substrate. Water changes can be made easier using a water changer like the Python water changer.

After introduction of new fish

When you have introduced new fish into your tank, it is advisable to put a little aquarium bacteria supplement in to help the transition. 

When you add more fish into any tank setup they will instantly create more waste to be broken down into ammonia, and will also excrete more ammonia directly too. This instant increase in ammonia present in the tank can overwhelm the bacterial colonies that are present in the tank until they catch up. 

Adding a little best aquarium bacteria supplement will instantly increase the amount of beneficial bacteria, cancelling out the increase in ammonia caused by the introduction of new fish.

How Much Aquarium Bacteria Supplement Should You Use?

Each manufacturer will have slightly different instructions on how much aquarium bacteria supplement you should use. 

In general, you should aim to use two teaspoons of bacteria supplement for every 10 gallons of tank water. This should give the bacteria the best chance of surviving the initial shock of the aquarium conditions and colonizing your tank. 

Always keep to the instructions on the particular brand of aquarium supplement that you have. If it differs from the two teaspoons per 10 gallons, go with what the bottle says!

11 Best Aquarium Bacteria Supplement Reviews

In the following section we will review the 11 best aquarium bacteria supplements on the market today. 

Remember that all of these are good solid options!

1) Seachem Stability

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Seachem Stability Fish Tank Stabilizer - For Freshwater and Marine Aquariums 500 ml
  • TANK STABILIZATION: Seachem Stability will rapidly and safely establish the aquarium biofilter in freshwater and marine systems, thereby preventing the #1 cause of fish death: "new tank syndrome".
  • TREATMENT: Stability is formulated specifically for the aquarium and contains a synergistic blend of aerobic, anaerobic, and facultative bacteria which facilitate the breakdown of waste organics, ammonia, nitrite, and nitrate.
  • BACTERIA GROWTH: The necessary conditions for the growth of Stability's bacteria strains encompass a very broad range. When other bacteria begin to die off (usually from high organic loads caused by the unknown death of an organism), Stability simply becomes more effective.

Seachem Stability is a great way to start off this list of the best aquarium bacteria supplement products. Unlike other aquarium bacteria supplements, it contains a synergistic mixture of aerobic, anaerobic, and facultative bacteria, with both nitrifying and denitrifying bacteria. Ammonia is therefore converted all the way through to atmospheric nitrogen. This is rare in bacteria supplements. 

Usually you will find products which only convert ammonia through nitrite to nitrate via nitrification. The fact that Seachem Stability also utilizes denitrification is brilliant, as it will prevent nitrate poisoning and well as new tank syndrome.

The bacteria used in Seachem Stability is very stable, and can survive in a wide range of conditions. Because of this you are guaranteed to have the full effect of the bacteria in your tank. The bacteria used aren’t sulphur fixing and are completely safe for your aquarium. It can be used in all freshwater, saltwater, and reef setups. 

Seachem Stability has a shelf life of 4 years, and doesn’t need to be refrigerated. The bacteria are in an inactive spore form, and are activated when they come into contact with the aquarium water.

Using Seachem Stability along with Seachem Prime Water COnditioner when undertaking water changes is a brilliant combination, as Seachem Prime will bind ammonia and nitrite into non-toxic forms, and also provide the bacteria in Stability with a good food source.

2) API Quick Start

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API Quick Start Aquarium Nitrifying Bacteria
  • Contains one (1) API QUICK START Freshwater and Saltwater Aquarium Nitrifying Bacteria 16-Ounce Bottle
  • Allows instant addition of fish when starting a new aquarium
  • Reduces compounds harmful to fish when used routinely
  • Helps prevent fish loss in freshwater and saltwater aquariums
  • Use when starting a new aquarium, when adding new fish and when changing water and filter media

API Quick Start is one of the most well known and best aquarium bacteria supplements on the market at the moment. With two nitrifying bacteria species, Nitrosomonas eutropha and Nitrobacter winogradski, ammonia is converted all the way to nitrate.

It comes in different sized bottles which is very handy; you can choose the bottle which is most suited for the size of your aquarium. There are 4 oz, 8 oz, 16 oz, and 32 oz bottles. We would recommend the 16 oz bottle as it will last a long time and keep you stocked with bacteria supplement.

API Quick Start is suitable for any freshwater or saltwater tank setup; however there is a separate API Marine Quick Start for saltwater tanks. You can choose the marine option by clicking the marine tab on amazon. The instructions are very clear, simple, and easy to follow. 

You don’t have to refrigerate this aquarium bacteria supplement which is very handy, so won’t have to put your bacteria next to your milk! 

3) Nutrafin Cycle Biological Filter Supplement

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Nutrafin Cycle Biological Filter Supplement, 16.9-Ounce
  • Fast-acting responsive ammonia and nitrite elimination
  • Consistent performance from each container due to bio-floc technology for improved shelf life and product viability
  • Ensures that biological pollutants produced by fish are rapidly converted to a non-harmful compound
  • Helps prevent fish loss
  • Suitable for freshwater and saltwater aquariums

The Nutrafin Cycle Biological Filter Supplement contains five species of nitrifying bacteria, and also contains a sixth waste control bacteria. 

These five species of bacteria enable it to be used in both freshwater and saltwater fish tank setups. Using this product quickly seeds your aquarium with nitrifying bacteria which will convert ammonia through to nitrate. 

Bio-floc technology preserves product stability, efficacy and shelf life. The lifespan of this bacteria supplement is 2 years at room temperature. However temperatures over 86°F (30°C) will significantly reduce the amount of viable bacteria in the bottle. It can be kept in the fridge but it is not necessary. 

This product is safe to use during tank cycling, water changes, and filter cleanings.

4) Instant Ocean Bio Spira Water Treatment for Aquariums

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Instant Ocean BIO-Spira Water Treatment
  • STARTS NEW aquariumS INSTANTLY Instant Ocean BIO-Spira accelerates the establishment of the bio-filter to prevent new tank syndrome
  • FOR SALTWATER TANKS Also use after a water change when adding new fish or after medicating
  • SHELF STABLE Does not require refrigeration
  • TREATMENT One bottle treats up to 75 gallons of water in marine aquariums
  • Age Range Description: All Life Stages

Instant Ocean Bio Spira is a brilliant bacteria supplement for saltwater and reef tanks. It isn’t for use in freshwater tanks, but for saltwater tanks there isn’t much better. 

A mix of live bacteria consisting of nitrococcus, nitrosomonas, nitrosospira and nitrospira is proven to work and start reducing levels of ammonia and nitrite immediately in your aquarium. These four bacteria are brilliant in converting nitrogenous compounds, and having multiple species increases the chance that there will be a bacteria which thrives in your tank.

Bio spira is very shelf stable, and so doesn’t need to be refrigerated. Simply keep it in the cupboard with your other fish tank supplies.

A bottle of Instant Ocean Bio Spira goes quite a long way; 5 mL treats 10 gallons of water.

5) DrTim’s Aquatics One and Only Live Nitrifying Bacteria

DrTim’s Aquatics One and Only are brilliant aquarium bacteria supplements, containing  live nitrifying bacteria to eliminate ammonia and nitrite from your tank.

There are different products specifically for freshwater and marine saltwater tanks; each is made with that environment in mind, so don’t use the wrong one!

If you have a saltwater tank you will need to turn off the protein skimmer that you are running or you risk removing the bacteria. You should also turn off the UV sterilizer if you are running one.

There are multiple sizes for both freshwater and marine bacteria supplements. There are 2 oz, 4 oz, 8 oz, 16 oz, 32 oz, 64 oz, and 128 oz options for both versions. The 8 oz bottle treats 120 gallons, so get the size most appropriate for your setup and needs. You will need to dose the aquarium with 2 capfuls (10ml) per 10 gallons.

They are sulphur and odor free, and the bacteria will stay viable for a long time. There is no need to refrigerate them. If you are using these for a new tank that hasn’t been cycled, when you can use ammonia drops alongside them to kick start things. 

6) MarineLand Bio-Spira Freshwater Bacteria

MarineLand Bio-Spira Freshwater Bacteria, for Starting New Aquariums
  • START A NEW AQUARIUM INSTANTLY Beneficial Marineland Bio-Spira Freshwater Bacteria prevents new tank syndrome and instantly cycles new aquariums when dosed as directed
  • IDEAL FOR Use when adding new fish for filter maintenance and during monthly water changes
  • ADVANCED NITRIFIERS Removes harmful ammonia and nitrate from aquarium water
  • REDUCES SLUDGE Includes heterotropic cleaner bacteria for a clear healthy aquarium
  • MAINTENANCE Add monthly as directed to replenish and boost beneficial bacteria

MarineLand Bio-Spira contains both live nitrifying bacteria to remove ammonia and nitrites and heterotrophic bacteria to remove sludge waste. These bacteria have been picked for their use in freshwater systems, so only use this product in freshwater tanks. 

This aquarium bacteria supplement has been designed to instantly reduce tank ammonia and nitrite levels when used as directed. 

One packet will treat 100 gallons of water, or in new tanks the whole packet will cycle a 40 gallon tank. For monthly maintenance needs you should use 10 ml, or 1 teaspoon, per 10 gallons.

It is ideal for new tank fishless cycling, and for use after monthly filter maintenance and water changes. It will greatly reduce new tank syndrome.

Bio-Spira does not need to be refrigerated, and has a one year shelf life unopened, and 6 months once opened. You should expect the tank water to go slightly cloudy when you pour this in, but don’t worry! It will clear up no problem.

7) Microbe Lift Nite Out 2 

MicrobeLift NiteOut II (16 oz)
  • Nite-Out II quickly decreases the ammonia and nitrite toxins in your aquarium, keeping your marine life safe by converting nitrite to nitrate through nitrosamines, nitrospira and nitrobacto strains inside of this liquid nitrifying bacterial formula.
  • Chemical free
  • Removes organic waste, ammonia and nitrate for clear, clean, nontoxic aquarium
  • Decreases ammonia and nitrite toxicity
  • Cycles a tank instantly when used with Microbe-Lift Special Blend

Microbe Lift Nite Out 2 contains a good mixture of Nitrospira and Nitrobacter nitrifying bacteria which convert ammonia through nitrite to nitrate. This works to prevent new tank syndrome by quickly cycling new aquariums and ensuring a healthy bio-filter in mature tanks.

Ammonia and nitrite are removed from the water column, removing the toxicity of these dangerous nitrogenous compounds, preventing ammonia poisoning and nitrite poisoning.

A new tank will be cycled instantly when using Microbe Lift Nite Out 2. Using it after water changes, tank cleanings, and when you add new fish into the aquarium to ensure that your biological filter is in good shape. 

Using regularly will ensure the continued removal of ammonia and nitrite from the water column, and ensure that concentrations don’t spike and poison your fish.

8) Easy-Life EasyStart

Easy Life USES 1000 Easystart
  • Bacterial booster for freshwater and marine
  • Starting up new aquariums and biological filters
  • Accelerated build up of useful bacteria and crystal clear water

Easy-Life EasyStart is an aquarium bacteria supplement which contains nitrifying bacteria to convert ammonia and nitrite to the much less toxic nitrate. It can be used to quickly cycle new aquariums and after adding new fish, after tank and filter cleanings, and after water changes to boost the biological filter.

Not only will the nitrifying bacteria provide stable and healthy ammonia and nitrite levels for your fish, but this product also cleans the water by removing heavy metals and other contaminants. This makes for an incredibly clean tank ecosystem.

For cycling new tanks you should use 10 mL per 40 gallons on day 1, 7, and 14. Overdosing is perfectly safe, so if you can always err on the side of adding more than necessary. 

Easy-Life EasyStart is for use in all freshwater, saltwater, and reef tank setups. 

9) Tetra Cleaning Bacteria

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Tetra Bacteria For Clean And Healthy Water
  • BENEFICIAL BACTERIAL BLEND: Replenishes beneficial bacteria to help filter pollutants in aquarium water.
  • BIOLOGICAL BALANCE: Works to keep your aquarium healthy and biologically balanced.
  • FOR SUPERCHARGED FILTRATION: Cleans gravel and removes sludge and ammonia.
  • CONVENIENT: Use the cap to measure and dose.
  • USAGE: Use monthly, or when setting up a new aquarium, after a water or filter change, or when adding new fish to ensure healthy water conditions.

Tetra Cleaning Bacteria contains multiple strains of bacteria which provide both nitrification and sludge removing processes. 

Using this aquarium bacteria supplement will quickly cycle a new tank, and will replenish the biological filter of mature tanks. This will ensure a healthy environment for your fish and will prevent dangerous ammonia and nitrite concentration spikes. 

The nitrifying bacteria convert ammonia and nitrite to nitrate, while the sludge removing bacteria will help to clean the substrate and provide you with a clean and clear aquarium. This works to make you substrate 30% cleaner than if you weren’t using this product.

You should use 10 mL of Tetra Cleaning Bacteria per 10 gallons of water. The cap can be used to measure out 2 mL, so you don’t have to get your teaspoons dirty!

10) Fluval Cycle Biological Enhancer

Fluval Cycle Biological Enhancer
  • All-natural water care creates a safe biological habitat to prevent fish loss by eliminating ammonia and nitrite
  • Infused with a powerful team of beneficial bacteria that immediately inoculates aquarium water
  • Extremely effective when setting up a new aquarium or introducing new fish to an existing one and useful during water changes and filter media changes, when good bacteria is depleted
  • Regular application helps to completely exclude establishment of undesirable bacteria
  • 16.9-ounce bottle for use in freshwater and saltwater aquariums

Fluval Cycle Biological Enhancer works to immediately cycle new aquariums, and to reintroduce nitrifying bacteria after medicating the tank or after water changes and cleanings.

Bio-floc technology ensures that this product is very stable and devoid of any contaminants that could otherwise harm your tank and fish. 

Fluval Cycle Biological Enhancer can be used in both freshwater and saltwater environments without any issues whatsoever. 

This all-natural aquarium bacteria enhancer creates a safe and clean habitat which will prevent fish loss as a result of new tank syndrome.

The solution in the bottle will separate as it sits in the cupboard, so you need to shake it well before you use it, otherwise you may not get the effectiveness that you desire and expect.

11) FritzZyme 9 Nitrifying Bacteria for Saltwater Aquariums

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Fritz Aquatics 80205 FritzZyme 9 Nitrifying Bacteria for Salt Water Aquariums, 32-Ounce
  • The Original Live Nitrifying Bacteria for Salt Water
  • Rapidly Eliminates Toxic Ammonia and Nitrite
  • Allows for Safe and Immediate Introduction of Livestock
  • Establishes and Maintains a Healthy Bio filter

The Fritz Aquatics FritzZyme 9 contains live nitrifying bacteria specific for saltwater aquariums. The bacteria strains used are saltwater specific, and guaranteed to reduce fish loss from ammonia and nitrite poisoning.

This aquarium bacteria supplement can be kept at room temperature. This product provides the proper balance of nitrifying bacteria proven to rapidly seed biofilters, therefore greatly reducing the natural cycle time. It also reseeds the aquarium after cleaning and maintenance. While care should be taken and water testing should be done, it should be safe to introduce fish immediate with this product.

The downsides are that this aquarium bacteria supplement can only be used in saltwater tank setups, as the strains of bacteria it uses will only survive in saltwater.

12) ATM Aquarium Products Colony Nitrifying Bacteria

ATM Aquarium Products Colony Nitrifying Bacteria comes in two versions; one for freshwater tanks and one for saltwater tanks. Both of these versions contain nitrifying bacteria to convert ammonia through to nitrate.

The freshwater version contains Nitrosomonas  and Nitrobacter to convert ammonia to nitrite and nitrite to nitrate, while the saltwater version contains Nitrococcus and Nitrosococcus to do the same job. Ensure that you buy the correct version!

Using this aquarium bacteria supplement eliminates the possibility of new tank syndrome from harming your fish, and enables you to add fish after days, if not the same day, rather than waiting weeks for the tank to cycle.

The dose is 4 oz per 25 gallons, and you should turn off UV sterilizers and ozone generators for 4-5 days after each dose. Otherwise these will kill the newly introduced bacteria. You should keep the bottle at room temperature; there is no need to refrigerate. 

Conclusion

Hopefully this article on the best aquarium bacteria supplement products has been helpful and given you good information on when and how you should use aquarium bacteria supplements, and what products are on the market. 

Our recommendation for the best aquarium bacteria supplement has to be Seachem Stability. It contains both nitrifying and denitrifying bacteria, so ammonia is converted to nitrite, nitrite to nitrate, and nitrate to atmospheric nitrogen. Having all these bacteria present is brilliant, and will stand your tank in good stead! It will prevent new tank syndrome, while also helping to prevent old tank syndrome as well.

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CoralRealm Staff

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