API Quick Start Freshwater & Saltwater Aquarium Water Treatment

Rated 4.125 out of 5 stars


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$8.48Chewy Price
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About This Item


  • Contains unique, patented nitrifying bacteria that start the cycling process, so fish can be added immediately.
  • Scientifically tested to help quickly consume ammonia and nitrite,
  • Can also be used during water or filter media changes, after medicating or when ammonia and nitrite are detected.
  • Limits toxic ammonia and nitrite levels.
  • For use when adding fish or changing water or filter media.

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Play Video: Learn More About API From Our Team of Experts
Learn More About API From Our Team of Experts

Special Note
  • 4-oz bottle treats up to 110 gallons.
  • 8-oz bottle treats up to 230 gallons.
  • 16-oz bottle treats up to 470 gallons.

Frequently Bought Together

This Item – API Quick Start Freshwater & Saltwater Aquarium Water Treatment, 4-oz bottle
Rated 4.125 out of 5 stars
$8.48Chewy Price

Buy 2, Get 3rd Free- Mix & Match

API Accu-Clear Freshwater Aquarium Clarifier, 4-oz bottle
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Total Price: $22.99

About API Water Conditioners

It’s Smart To Be Proactive!

The best way to keep your aquarium clean is to maintain good water quality. This will help keep your fish strong and vibrant and prevent disease. Water conditioners and test kits from API can help you keep your aquarium water safe and healthy.

How Do I Maintain a Healthy Environment?

It is important to test your aquarium water weekly to ensure it stays healthy for your fish.  In addition, a bi-weekly partial water change of no more than 25% will help reduce toxic buildup, remove debris the filter missed, and replenish the oxygen available to your fish.

Feed Twice Daily and Test Water Weekly

Feed your fish twice a day, check their water temperature, and observe them to make sure they are active. You should also test water quality weekly for optimal safety. For fish to thrive, their water must closely match that of their natural environment—poor water quality can cause stress, illness and even fish loss. The 6 important parameters for healthy aquarium water are ammonia, nitrite, nitrate, pH and water hardness (GH & KH). All of these can vary over time and are invisible to the eye.

Change Water and Restore the Ecosystem

In a closed aquarium environment, there are no natural rivers or streams to carry away debris and other waste materials. That is why you should replace 25% of your aquarium water every two weeks, making sure to add water conditioner to your tap water to make it safe for your fish. You should also change your filter media and clean your gravel monthly. Adding beneficial nitrifying bacteria with API Quick Start when you do will help restore your aquarium’s fragile ecosystem and avoid disruption.

What Do API Products Do and When Do I Use Them?

API Test Kits

Use test kits weekly to monitor water quality parameters, which can vary over time and impact the health of your fish.

API Stress Zyme

Using this every week will help keep your aquarium clean and your gravel and ornaments sludge-free.

API Algaefix

Use weekly to control algae growth and keep aquarium glass, ornaments and plants clean.

API Stress Coat

Use every 2 weeks during water changes to make tap water safe, and when adding fish, or when fish are injured.

About API

The team at API has a passion for fish and understands the rewards and relaxation fishkeeping can bring. For almost 60 years, they have developed premium products with a focus on proven and effective results. API offers a range of testing kits, water conditioners and nutritionally superior fish foods. They are dedicated to making a better underwater world for the benefit of fish and those who keep them.

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Fish TypeBetta, Bottom Feeder, Cichlid...Betta, Bottom Feeder, Cichlid...Cichlid, Goldfish, Marine Fish...Betta, Bottom Feeder, Cichlid...Betta, Bottom Feeder, Cichlid...
Aquarium TypeSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, FreshwaterSaltwater, Freshwater

Questions & Answers

9 Customer Questions

What is the difference between this and API's Tap Water Conditioner?
Answer by ChewyJun 12, 2018
The Quick Start treatment is needed more for adding fish, water and filter media changes for an already established tank while the API Tap Water Conditioner is for beginning a brand new tank.

if I add quick start will I still need stress coat?
Answer by ChewyJul 01, 2019
API Quick Start is primarily used when adding fish, changing tank water, and performing filter media changes in an already-established tank to boost the natural aquarium cycle, as it helps to quickly consume ammonia and nitrite levels. API Stress Coat removes chlorine and neutralizes chloramines and heavy metals found in tap water. These treatments may be used together and will benefit your aquarium in different ways.

Can I add fish immediately after adding Quick Start to my tank?
Answer by ChewyApr 12, 2018
API Quick Start Aquarium Water Conditioner allows you to add your fish immediately after using.

I used when I set up my new tank. Should I put it in each 10% water change? As I plan to do this every few days for the first week or two
Answer by ChewySep 26, 2019
The first time using this treatment you should shake the bottle well then add 10 ml per 10 U.S. gallons of aquarium water. For saltwater aquariums, double the dose. For maintenance you can do this once a month.

ReviewsWrite a Review

Rated 4.125 out of 5 stars
32 Ratings
Would recommend to a friend

32 Customer Reviews

Rated 1 out of 5 stars
By Karmc on Sep 26, 2023

Waste of money….

This product has done nothing to lower Nitrite levels in my cycling tank. I won’t buy again. Waste of money.

Rated 5 out of 5 stars
By jules on Nov 1, 2022


Ordered discus from Jack Wattley. Gorgeous. Accidentally put the bag water in my tanks and killed my biofilter. Huge ammonia spike. Hundreds of dollars of discus floating on top and bottom. In addition to massive repetitive water changes, quick start saved me and the fishes. Amazing! Also, chewy associates always the best.

Rated 5 out of 5 stars
By Shell on Feb 28, 2023

Thank you

Thank you so much for the product it really helps take care of my fish.

Rated 5 out of 5 stars
By Lilly on Nov 16, 2022

Review on quick start

I love the api quick start. It is a very good product.

Rated 5 out of 5 stars
By Michelle70 on Feb 27, 2022

Great product

I have been using Quick Start for about a year and my fish tank looks fantastic. The levels in my tank are perfect.

Rated 4 out of 5 stars
By Huffnpuff on Jan 29, 2022

No problems with start up

used this product to start up a 29 gallon aquarium with no problems. Fish were added in 24 hours And it’s been fine so far.

Rated 5 out of 5 stars
By JBOB on Jan 21, 2022



Rated 5 out of 5 stars
By Giasmom on Nov 28, 2021

Works as specified

I always put this in when I do a water change in my fish tank. Keeps the water healthy for my fish.

Rated 5 out of 5 stars
By Hannah on Oct 9, 2021

Good stuff

Love this product, it is great!—————————————————————————————————————/-——————————————-

Rated 5 out of 5 stars
By MissElly2 on Jun 22, 2021

love this stuff!!

We've used this product since the original setup of our fresh water tank. It's great for tank maintenance too. And the price i paid thru Chewy saved us almost $20. Working on a fixed income, this fit in our budget perfectly.