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The 10 Best Aquarium Bacteria Starters

Setting up a new aquarium is a lot like creating a whole new world. It's not as easy as saying "Add water, then fish." To keep an aquarium healthy, everything, even the things you can't see, needs to be in good balance.

Aquarium bacteria starters speed up the cycle for a new aquarium because they quickly create a healthy bacterial colony that is ready to deal with harmful amounts of ammonia and nitrites.

The most common type of bacteria starter for an aquarium is a liquid. This is because it dissolves quickly in its new environment and starts to grow the colony right away. Remember that all of these products have live bacteria and, because of that, a shelf life.

Not all of them are the same length, though. After bacteria have settled on the bottom of a bottle, shake it well to mix it up. If it smells bad, the bacteria may be dead.

BestForPets (bestforpets.org) has done all the hard work and put together this list of in-depth reviews to help you find the best aquarium bacteria starters for your specific needs.


The one and only nitrifying bacteria sold by Dr. Tim’s Aquatics

The purpose of Dr. Tim’s Aquatics is to get rid of ammonia and nitrite. It works right away to stop toxic buildup, which is often called “New Tank Syndrome.”

Use One & Only when you get a new tank, after treating a disease, or when you change the water every month. There are no smells of sulfur or anything else that is unpleasant.

Dr. Tim’s product controls the amount of ammonia and nitrite in the water and naturally gets rid of toxic substances. In either a freshwater or saltwater aquarium, it does this.

After using the compound, the fish can go right back into the tank. Make sure the company sends you a new bottle, because bacteria die in old bottles and they are no longer useful.


  • Can add fish right after that
  • Natural way to get rid of toxins
  • There are no bad smells.
  • Useful for both freshwater and saltwater tanks


  • Older bottles don’t work as well.


Fluval Hagen

Fluval Hagen works well to bring nitrites and ammonia levels that are too high or too low to zero quickly. With Fluval Hagen, you can get rid of the buildup that can happen in new tanks or when the water changes.

Some people were able to cycle in a new tank right away, while others had to wait a few days. Some people had to wait longer, and they suggested getting an API test kit to check the levels of nitrite and ammonia in the water before putting the fish in.

Make sure to shake this bottle before you use it because the live bacteria settle to the bottom. Fluval is the best bacteria starter for an aquarium you can buy for the money.

It helps the good bacteria around the tank grow more quickly so they can eat the harmful nitrates and ammonia.


  • You can add fish right away
  • Makes tank cycling easy.
  • Best value price


  • Bacteria in old bottles don’t work as well.


MarineLand Bio-Spira

If someone wants to start a new aquarium, they don’t want to have to wait days or weeks to get it going. When looking for products to use in the development of the tank, it is very important to avoid “new tank syndrome.”

Even though Bio-Spira is more expensive than some of the other options on our list, you can be sure that it is for a good reason.

Bio-Spira lets aquarium owners start up their new tanks faster than most other systems. It gets rid of any harmful toxins by using advanced nitrifiers and even cuts down on sludge by adding heterotrophic cleaner bacteria.

Marineland’s packaging helps bacteria live longer, so you can be sure that your pouch is healthy.


  • The packaging at Marineland keeps bacteria alive longer.
  • Makes a better balance of bacteria quickly.
  • Good for emergencies on the bike


  • A little more expensive than other things.


API Quick Start

The API Quick Start, which comes in a 16-ounce bottle, gives you more for your money. It’s advertised as a cleaner that lets you add fish right away, but you should be careful if you’re cycling a brand-new tank.

When used regularly, this natural cleaner helps cut down on the number of chemicals that are bad for fish. Both freshwater and saltwater aquariums won’t lose fish because of this change.

It is suggested to use it when setting up a new aquarium, adding new fish to an aquarium that already has fish living in it, or changing the water or filters.

Be careful when you use this product, because it doesn’t work exactly like it says it does on the bottle. Since API Quick Start doesn’t have any ammonia, it doesn’t give the bacteria anything to do to start the process.

Make sure to put in ammonia before the bacteria, and then the cycle for a new tank should start.


  • Contains good bacteria
  • When used often, it works quickly.
  • tries to fix problems with bacterial colonies in an emergency


  • API doesn’t have any ammonia to help start the tank’s cycle faster.


Tetra SafeStart

Many people who like fish highly recommend Tetra SafeStart because it prevents “new tank syndrome” by making healthy bacteria grow faster. This product gets rid of harmful levels of ammonia and nitrite by turning them into useful nitrates in a clean way.

Even though it doesn’t happen right away, it does speed up the water cycle so that their new home is healthy when you bring them in.

The product does have live bacteria, which may settle to the bottom. You should give it a good shake to help them spread out. There is enough in the bottle to clean up to 100 gallons of fresh water.


  • Works on water up to 100 gallons
  • Helps turn dangerous chemicals into nitrates
  • All-natural


  • This product works more slowly than others.
  • Only for tanks with fresh water


Brightwell Aquatic

Brightwell Aquatics has made a way to grow a full bio-culture in new tanks and improve the water quality in them.

Their product works to set up biological filtration by reducing the number of harmful compounds like nitrate and phosphate. It can be used to change the way the water in both saltwater and freshwater aquariums feels.

The product is not only backed by the company, but it has also been tested and given the OK by a veterinary pathologist. The product has more than one use.

It not only helps filter out toxins by making healthy biocultures, but it also gives the fish and bacteria the essential nutrients they need.


  • Does wonders for reef aquariums that need it the most.
  • Slow working to avoid changes that are bad for animals
  • More harmful toxins are removed than with other products.


  • Slow-acting



Nite Out is advertised as a product that gets rid of harmful toxins quickly and can be used in emergencies to save fish. It helps the fish stay healthy by turning nitrite into nitrate. It is made up of liquid nitrosamines, nitrospira, and nitrobacter strains.

Once this chemical-free product is put into a tank, it works to get rid of organic waste, keep ammonia and nitrate levels in check, and create a safe environment for aquarium fish. The fact that the water in the aquarium becomes crystal clear is proof of this.

When used with the Microbe-Lift Special Blend, this product works well to get a new tank up and running right away.


  • Fast to work
  • Sets up bacteria effectively
  • Chemical-free
  • Makes a tank as clear as glass.


  • Works slower on saltwater tanks


Fritz Aquatics FritzZyme 7 Bacteria That Remove Nitrogen

Fritz knows that it can take weeks for nitrifying bacteria to grow in a new aquarium. It has also learned that the levels of ammonia and nitrate can rise so quickly that they can kill in a matter of days or even hours. This is why they have put together several types of bacteria to put in a new tank so that colonies can start up quickly.

With FritzZyme, you should be able to add new animals to an aquarium right away and give them a healthy place to grow.

For best results and maintenance, the product can be used after changing the water, when adding new fish, after a hard cleaning, or when taking medicine or changing the filter media.

When you get the product, make a note of whether it smells like sulfur or rotten eggs. People have said that this item doesn’t last long.

If the smell is there, it probably means that the bacteria inside are dead. To keep the product from going bad quickly, store it in a cool, dark place.


  • has different kinds of bacteria
  • Get results fast


  • Short time to use
  • Details about how to store


The health of all the animals and plants in your tank depends on keeping their environment clean and well-balanced.

Even after setting up a new tank, it needs to be taken care of regularly. Bacteria starters are natural substances that can be used to make biofilters work right away.

If you don’t know what you need, it can be hard to compare options for any product. Find out how each product works by doing research.

Even though there are a lot of different products on the market, BestForPets (bestforpets.org) hope this list made it easier for you to find the best aquarium bacteria starters that fit your aquarium’s needs.

Buyer's Guide

If you spent money on the fish and other things in your tank, you want to make sure they live as long as possible and stay healthy.

One of the best ways to do this, both when the tank is new and when something changes in the tank’s environment, is to use bacteria starters.

An aquarium bacteria starter should help make a natural biofilter that keeps harmful bacteria and toxins from getting into the water.

There are still differences in what different products are made to do. It’s good to know about these things because they help you choose the best food for your fish.

Product Lifespan

Almost all of the products above have talked about how long they will last. These starters have a limited life because they contain live bacteria that are useless after they have “expired,” or died.

Some products may need to be kept in the fridge to keep them fresh longer. Others have specific instructions for how to store them to keep the colonies inside them happy and healthy.

Make sure to do research on this before you buy something, and choose based on how much space you have and what you like.

Tank Size

For different sizes of tanks, different aquarium starters are made. The size of the tank is important because some of the amounts and ratios in the starter formula will change depending on how big or small the tank is.

They may also need different-sized doses based on their size, which means they may need more or less of the product to work. Each starter is different, so read the directions carefully.

What Kind of Starter

There are three different kinds of things that start the bacteria in an aquarium. They can be liquid bacteria in a bottle, bacteria that have been dried out in bags or containers, or bacterial supplements.

Each of these three types of starters does something a little bit different and works best in different types of tanks. The choice depends to some extent on what you want and what you need it to do.

Clean the fish tank.

When you buy any kind of aquarium starter, make sure it has real nitrifying bacteria that arrive alive every time. Check the list of ingredients and do some research to make sure it is safe.


Lastly, think about how much the product costs compared to how much you get. There are a lot of good products on the market that don’t cost too much. Choose a price range that you feel good about and then do your research.

Author Image

Dr. Deborah Fletcher

Deborah R. Fletcher, DVM, is a skilled veterinarian with more than 15 years of experience dealing with companion and exotic animals. She has experience caring for a variety of animals, including household cats and dogs, reptiles, birds of prey, and even primates. Dr. Fletcher is a valuable part of the BestForPets team, where she contributes to their aim of providing pets and their owners with the finest possible treatment and services.

Veterinarian (DVM) Dr. Deborah Fletcher


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