Koi Defender (32oz)
$60.99
Price: $60.99
(as of Oct 25, 2025 13:06:25 UTC – Details)
Product description
Koi Pharma – Your Koi’s Best Defense Starts Here
Trusted Science. Proven Care. Peace of Mind for Every Pond.
At Koi Pharma, we believe that every koi keeper — from passionate hobbyists to seasoned professionals — deserves access to treatments that are both effective and trustworthy. Founded in 2022 after more than 20 years working with high end imported koi, our mission is to provide innovative, science-driven solutions that safeguard the health of koi and goldfish year-round.
Our journey began with a clear need: a new, viable option for fish health care that truly works. Backed by veterinary expertise, scientific literature, and years of real-world field experience, we developed products that go beyond what the market currently offers. Where other brands stop, we innovate. If a product is essential, we make it stronger, purer, and easier to use. If the market is missing a solution, we create one.
Koi Defender
KOI PHARMA introduces Koi Defender, the ultimate solution for protecting your koi from harm. Koi Defender is a premium blend of beneficial bacteria and natural enzymes designed to support a clean, balanced pond environment for koi and goldfish. Koi Defender helps create a pond environment that naturally discourages imbalances and conditions often associated with harmful bacteria. This high-potency formula is ideal for regular pond maintenance and proactive wellness support, helping koi enthusiasts maintain vibrant, healthy fish without disrupting biofilters or beneficial microbes.
DOSAGE
Add 4 tsp (20 mL) per 1,000 gallonsDose every 3 days, for 3 treatments total
Then continue with 1 dose per week for 2 weeks
Add 2 tsp (10 mL) per 1,000 gallons Once a week, every week Use throughout pond season for best results (above 50°F)
50°F – 62°F: Use 2x dose63°F – 69°F: Use 1.5x dose
70°F and above: Use standard dosage
FEATURES and BENEFITS
BENEFICIAL BACTERIA
Beneficial strains of bacteria specially selected to improve water quality and fish vigor while creating conditions unfavorable to undesirable bacteria.
SAFE FOR KOI AND ALL OTHER POND INHABITANTS, PETS WILDLIFE AND PEOPLE
Safe for all fish & other pond inhabitants, wildlife, pets and people when used as directed.
EASY TO DOSE LIQUID FORMULATION
Liquid formulation for easy application to the pond.
HIGHLY CONCENTRATED FORMULA
50X more concentrated than competitive products.
Built on Experience. Driven by Science . Trusted by Professionals and Hobbyists.
Where Experience Meets Innovation
Our Team brings decades of hands-on experience in koi keeping, aquatic health and pond care.
Every Koi Pharma product is developed with the same expertise, precision and care we apply to our own koi collections because your fish deserve no less.
Where the Innovation Begins
At our specialized facility, research and experience come together to create the most advanced koi care products available.
Proudly made in the USA – where quality, safety and koi health come first.
Internationally Trusted By Koi Experts
Koi professionals internationally trust Koi Pharma products to support healthy, thriving fish.
Our solutions are the choice of those who demand expert care and proven results wherever koi are kept.
Item Weight : 2 Pounds
Item model number : KDefender32oz
Date First Available : March 9, 2025
Manufacturer : Koi Pharma
ASIN : B0DZW2G9J5
Best Sellers Rank: #62,997 in Pet Supplies (See Top 100 in Pet Supplies) #34 in Fish Medication & Health Supplies
Customer Reviews: 5.0 5.0 out of 5 stars 10 ratings var dpAcrHasRegisteredArcLinkClickAction; P.when(‘A’, ‘ready’).execute(function(A) { if (dpAcrHasRegisteredArcLinkClickAction !== true) { dpAcrHasRegisteredArcLinkClickAction = true; A.declarative( ‘acrLink-click-metrics’, ‘click’, { “allowLinkDefault”: true }, function (event) { if (window.ue) { ue.count(“acrLinkClickCount”, (ue.count(“acrLinkClickCount”) || 0) + 1); } } ); } }); P.when(‘A’, ‘cf’).execute(function(A) { A.declarative(‘acrStarsLink-click-metrics’, ‘click’, { “allowLinkDefault” : true }, function(event){ if(window.ue) { ue.count(“acrStarsLinkWithPopoverClickCount”, (ue.count(“acrStarsLinkWithPopoverClickCount”) || 0) + 1); } }); });
Comprehensive Protection
High Potency Formula
Safe and Effective
Use Weekly
Customers say
Customers find the water treatment effective for their koi, with one mentioning it keeps fish safe throughout the year and another noting it works well in both ponds. They consider the product good value for money.
john janhsen –
This product works amazingly well.
I have been using the Koi Defender for a while now. Saw that Amazon sold it, so thatâs why I ordered it on Amazon instead of driving to the Koi Market. It was much more convenient for me to do so. I think it works extremely well for both of my ponds.The Koi defender is a prophylactic treatment. It is a specialized bacteria. The bacteria specializes in going after and reducing the nutrients and food sauce for the pathological bacteria. It basically starves them out of your ponds ecosystem. Reducing the redness, rot and ulcerations when starting up the pond for the season. I use it on a weekly basis when the temperature of the pond reaches 50° to the end of the season when again you water temperature is at 50°. You canât use it below 50°. It wonât work as it was designed to if you do.I highly recommend this product. I bought a gallon because like I said, I have to ponds. You also will love this product once you start using it.
Estelle C. –
Excellent product
I really can say enough about Koi Defender and the entire Koi Pharma product line. My Koi are healthy and thriving thanks to Koi Defender. The Koi Market staff goes out of their way to help with any questions or concerns when it comes to Koi, pond health and all the Koi Pharma products.
Amazon Customer –
This stuff rocks
This stuff is great. Itâs been a game changer in the spring while my koi are still adjusting and vulnerable to bacteria/parasites. Great to have extra for emergencies or to just keep the fish safe throughout the year. The team at Koi market are super responsive and knowledgeable. Fantastic resource for all Koi enthusiasts.
mannaa96 –
Defend your Koi!
Why did you pick this product vs others?:I have two ponds with high quality Koi imported from Japans top breeders, many that have taken home awards at shows like ZNA etc. Most of my Koi are 28 inches or bigger some nearing 3 feet. I only trust a koi defender to keep my Koi safe from bacterial disease, I use this as a preventative measure weekly, but have also used it to knock out some pretty rough aeremonas causing ulcers in my back pond when I first started in the hobby after a bad batch of Lillieâs introduced some nasty bacteria into my pond. Love this product 5 stars. Well done Koi PharmaÂ
Nelson Mangubat –
Koi defender is great!
Koi defender is a great product. It prepared my quarantine tank from unwanted diseases. Highly recommend.
Matthew W. –
Actually helpful
I’ve had a well established ponf for years…last fall i lost my first fish in years…then a second one in the spring and the remaining koi were scratching…since treating with this no additional losses and koi havs stopped scratching
Rachelle –
Great options to keep your Koi fish healthy year round!
My husband and I are Koi enthusiasts. We do everything we can to assure our koi are healthy and happy year round! After finding Koi Pharmas website we started to try their amazing products and we are very pleased with the results so far! So much so we have even decided to become vendors ourselves through them. Definitely would recommend giving their company and their products a try for the overall health and treatment of you koi!
Allen –
Defend your Koi!!!
I don’t normally leave reviews, but this product really delivers. This is a replenishment of a fantastic prophylactic treatment for koi. If you want to start your koi off on the right fin ( foot ), treat your pond to some preventative piece of mind. You and your fish won’t be sorry.