Want to add fish quickly and safely to your new fish tank? Then you’ll need to kick start the nitogen cycle with the help of a bacteria supplement.
If your tank is already established and you want to add more fish or after a water change, you want to make sure that the biological balance in your fish tank is maintained. Bacteria supplements will help you achieve this.
We review the best aquarium bacteria supplements to get your fish tank started and keep it maintained below.
Table of Contents
Top 5 Fish Tank Bacteria Supplements
| # | Preview | Product | Quick Review |
| 1 |  | ATM Colony | Fastest and Best Overall |
| 2 |  | Dr. Tims One and Only | Takes Time |
| 3 |  | API Quick Start | Maintainance Only |
| 4 |  | Brightwell Aquatics Microbacter7 | Care Needed |
| 5 |  | Fluval Cycle Biological Enhancer | Maintainance Only |
Why You Should Use A Bacteria Supplement
New Fish Tanks: All new fish tanks require biologically cycling before you add any fish. Fish waste produces ammonia which is toxic to your fish.
In the wild the nitrogen cycle uses naturally available good bacteria to convert this ammonia into first, nitrites and then nitrates (which are not so harmful and can be removed by water changes).
This process takes time in your fish tank (up to 6 – 12 weeks) but can be greatly speeded up by adding a bacteria supplement to your tank.
Established Tanks: If your tank has been running a while and you want to add new fish then be aware that more fish means more waste. To enable your system to cope it’s best to add a bacteria supplement to ensure that any additional ammonia is processed and removed.
Water Changes: Water changes, whilst removing excess nitrates from your fish tank, may also remove some good bacteria so you should add a bacteria supplement to compensate and keep your tank in balance.
What to Look for When Buying a Bacteria Supplement
Fresh or Saltwater : Just be aware that some bacteria supplements are for freshwater only or saltwater only. Some products offer a freshwater or marine version and some can be added to both.
New or Established Tank: Some bacteria products are specifically designed to be added to new tanks to kick start the nitrogen cycle. Others are better for maintaining the biological balance in established tanks.
How long do they take to work: Some bacteria products claim to work instantly and that you can add fish straight away to a new tank. Others, that it may take a few days or weeks for the bacteria to become established
A quick word on dechlorinators: If you use tap water to start your fish tank or for water changes you must dechlorinate it first. Tap water contains chlorine to make it safe for us to drink but it’s bad for your fish so must be removed.
Dechlorinators can be purchased from any good aquarium store or online but they are different products to the bacteria supplements discussed in this article.
Bacteria Supplement Product Reviews
Here are my reviews of the best aquarium bacteria supplements products:-
1. ATM Colony
ATM Colony has been specifically formulated for use in new fish tanks. It contains millions of nitrifying bacteria to establish your bio-filtration in the quickest way possible.
It prevents any ammonia or nitrite spikes so you can add fish straight away to a new tank. Add just a few fish to start with and feed sparingly for the first few days whilst keeping an eye on ammonia and nitrite levels.
It’s also great for when you add more fish or after tank maintenance, filter cleaning and water changes.
Whilst not designed for fishless cycling it can be used provided you add an ammonia source at the same time.
Pros
- The best bacteria supplement for new fish tanks
- Freshwater and marine versions available
- Add fish straight away
- Great for ongoing tank maintenance, water changes, etc
- Does not require refrigeration
Cons
- Not to be used with other bacteria supplements
2. Dr Tims One and Only
Dr Tims One and Only is designed for use in new fish tanks when fishless cycling. Used in conjunction with a separate ammonia source it can reduce the time it takes to cycle your tank to around 5 -7 days (though anecdotal evidence suggests it may take up to 30 days).
You can either add your own ammonia source, by ghost feeding for example or purchase separately DrTim’s ammonium chloride solution.
Dr Tims One and Only is not suitable for use after water changes, adding new fish or filter maintenance.
Pros
- Can be used in new tanks
- Fresh and Saltwater variations available
Cons
- Requires a separate ammonia source
- Not designed for ongoing maintenance
3. API Quick Start
API Quick Start contains nitrifying bacteria to kick start the nitrogen cycle in a new tank. Whilst API claims you can add new fish straight away we’re not sure you should risk it.
It can take at best, 10-14 days to fully cycle your tank so we’d advise cycling your tank without fish when using this product and adding a separate ammonia source to start the process.
API Quick Start can be used for ongoing maintenance.
Pros
- Can be used in both fresh and saltwater aquariums
- Low cost
Cons
- Not the best for new tanks
4. Brightwell Aquatics Microbacter7
Microbacter7 has been specifically formulated to establish biological filtration in new aquarium set-ups but it can take up to 2 weeks to fully cycle your tank.
Thereafter it can be used as an ongoing supplement but care is needed with the dosage or it may lower nutrients too far.
Best added to an external filter. With a saltwater aquarium, protein skimmers should be turned off for up to 4 hours after dosing.
Pros
- Can be used in both fresh and saltwater aquariums
- Low cost
- Lowers nutrients
Cons
- 2 weeks cycle time for new tanks
- Care needed
5. Fluval Cycle Biological Enhancer
Fluval Cycle Biological Enhancer contains nitrifying bacteria that can speed up the cycle time on new tanks but not by much.
It is more effective if used for ongoing maintenance or when adding any new fish.
Pros
- Can be used in both fresh and saltwater aquariums
- Low cost
Cons
- Not for new tanks
Conclusion
ATM Colony is my ‘go to’ aquarium bacteria supplement for new fish tanks. You can add fish instantly and be sure your fish tank’s biological filtration can cope.
It also doubles up as bacteria supplement for ongoing maintenance so really is a one-stop-shop for your fish tank’s bio-filtration needs.
Bacteria Supplement FAQs
Here are some commonly asked questions on bacteria supplements.
How long does it take for beneficial bacteria to grow in an aquarium? – Left to nature, beneficial nitrifying bacteria take around 4 – 8 weeks to establish themselves fully in your tank and the nitrogen cycle to be completed. A bacteria supplement will reduce the time it takes to 1 -14 days.
Do aquarium bacteria starters work? – Yes they do. Adding a bacteria starter supplement will greatly speed up the time it takes to cycle your tank. This can range from instantly to around 14 days depending on which supplement you use.
How quickly does a bacterial starter work? – It depends upon which supplement you use. Typically, a bacteria supplement will cycle a tank in 2 – 14 days. The better ones cycle a tank instantly allowing you to add fish straight away.
When can I add fish after using a bacteria supplement? – It depends upon which supplement you use. Some allow you to add fish straight away and others just speed up the cycling process.
Can I use an aquarium bacteria supplement to cycle a new tank? – Most definitely. Most are designed for this specific purpose but some are faster at cycling a tank than others.
How often should you use a bacteria supplement in an aquarium? – Even after your tank has cycled you should continue to use a bacteria supplement after water changes or adding new fish. If you have a sudden ammonia or nitrite spike use a bacteria supplement to help reduce harmful levels.
Can you add too much beneficial bacteria to a tank? – No, you can’t have too much of a good thing. Always follow the instructions on the product but you can’t overdose.
Should I remove carbon when using a Bacteria Supplement? – No it’s not necessary. Carbon removes excess nutrients and not good bacteria.
Can I use different Bacteria Supplements at the same time? – Not always. Some will offset the effects of others and stop them working properly so always carefully follow the product instructions.