How to… Compiling a Koi first-aid kit

A Koi first-aid kit is vital to keeping fish healthy – make sure you’re the head of the health class by reading James Careless’ essential guide to compiling and using a perfect Koi first-aid kit…

Why have a Koi first-aid kit?

For pets, Koi are remarkably hardy creatures. But illness and injury can strike these domesticated carp; commonly in the form of angry red skin ulcers, parasites, or general poor health due to toxic water conditions.
When trouble strikes, you want to be ready to provide first aid fast. But what can an average Koi keeper do when it comes to providing appropriate first aid to fish, and what tools and medicines should they have on hand?

Emergency situations

You can helpt prevent your Koi from getting ill or injured, but they will not protect them entirely.

“Emergency situations can occur because of unexpected events, such as power cuts due to storms or local accidents in the power supply, predators such as herons attacking Koi when they’re in the pond, or even heavy rain causing water to flow into the pond carrying fertilisers, oil or insecticides from the surrounding environment,” explains Dr Nick Saint-Erne, DVM. He is a Quality Assurance Veterinarian for PetSmart, and the author of a profoundly useful book called Advanced Koi Care. “Other health risks can be caused by the introduction of contaminated Koi into your pond. This is why smart Koi keepers quarantine newcomers in a tank of their own for 14–21 days, to see if they are truly healthy.”

First-aid training
Typically, when a family dog or cat is ill or injured, their owners take them to the vet. But this is usually not an option with Koi. Even if you do have a way to transport them by car, Koi vets are few and far between.

This problem is not limited to the UK. “In Phoenix, Arizona, I have not been able to find a KHA (a Koi Health Advisor trained and certified by the Associated Koi Clubs of America)” says David ‘Shorty’ Routh. He runs Phoenix Koi Rescue (; a remarkable group of volunteers who find new, caring homes for Koi living in too-small and toxic conditions. In fact, when American Koi are sick, people call either him or their local
Koi dealers. “If there is a KHA in Phoenix that will deal with the public, let me know!”

What you need
Before you start assembling a Koi first-aid kit, you should have an idea when and how you will need to use it. This is why having a few reliable books on your bookshelf is a good bet. There are many great books out there. The two that my wife and I use as our personal bibles are Dr Saint-Erne’s Advanced Koi Care, and Dr Erik Johnston’s Koi Health & Disease. Dr Johnston’s book is sold at his site,

In terms of usefulness, I always start with Koi Health & Disease whenever my Koi have health issues, followed by Advanced Koi Care. Although both books are must-haves, Koi Health & Disease is an easier read for lay Koi keepers. This said, both books are invaluable for helping you diagnose symptoms and compile a plan of attack, and I think it’s wise for any Koi beginner to find a basic health book to help them through any problems.

If you are reading this now and your Koi is sick – and you don’t have time to wait for a book in the post – don’t despair: there are many websites out there that can offer you assistance. Dr Johnston’s website offers lots of useful tips at His site is not the only Koi health site out there; take a look at or or ask for some advice on one of the many popular forums out there.
In short, don’t panic: there is information available to guide you through Koi first aid and what needs to be done. These books and sites will also help you decide when you can help, and when you cannot.

Kit essentials
What should a Koi first aid kit include? “A tank or paddling pool with a net cover and its own aeration system,” replies Shorty; “preferably 150 gallons or larger. You also need salt, baking soda, formalin, malachite green, a product that removes ammonia and nitrite, and a backup pump in case your main pump fails and you need to cycle your pond’s system”.
“A microscope, wound cleanser [like iodine or Betadine], wound sealer, cotton buds, and an anaesthetic like MS222” says UK Koi keeper Bernie Woollands. “I deliberately don’t hold pond and disease treatments and chemicals. I prefer to buy them if and when I need them. I don’t want them going out of date.”  You can also use clove oil as an anaesthetic for Koi.

That said, an ammonia and nitrite remover is something you should always have available for water changes. “Other water conditioners can remove copper and other heavy metals, or add mucus enhancers,” Dr Saint-Erne notes. “Bacterial supplements can be used to increase the beneficial bacteria colonising the biological filtration media in the filter. This is especially helpful in new ponds or when you’re increasing the number of fish in an existing pond.”

He also adds that you should not forget a water test kit. “The dip strips are fast and inexpensive, but not as accurate as the other test types, although they do work. They should be able to test for ammonia, nitrite, nitrate, pH, hardness, alkalinity and temperature. Other tests can include salinity, conductivity, dissolved oxygen, copper,
and phosphate.”

Water and oxygen
For a quick injection of dissolved oxygen to your water, use hydrogen peroxide (3%). “This can be used in an emergency power failure to increase the oxygen content of the water when the filtration is off,” says Dr Saint-Erne. “Add 1mg of water daily to raise the dissolved oxygen content. Stir vigorously to disperse the peroxide in the pond water. Add some into the biological filter as well, to provide oxygen to the bacteria in the biofilter to help keep them alive during power outages.”

Other must-have items include a quality long-handled, appropriately sized Koi net; a plastic container for holding your patient after it is removed for inspection, and an aquarium air pump with airline tubing and an airstone to ensure that the container water is sufficiently oxygenated. If you keep the patient in a small tank, keep a close eye on the water quality. The smaller the tank, the sooner the water goes bad.

As for water, fill the container and any holding tanks with the same water that the fish came out of if at all possible; unless it is shown to be diseased. If it is, the new water should be as close in temperature and pH to the original water as possible. If the original water was too low in pH, consult your books to bring the holding tank water up to an acceptable pH (7.0–7.5) over a safe time period, otherwise you run the risk of shocking your patient!
Finally, have latex gloves handy. When you remove your fish, try to touch them as little as possible, to avoid removing their protective mucus layer. Wearing gloves yourself also provides your patient with extra protection against infection.