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How do I know if my koi pond fish have parasites?

Koi Parasites

How do I know if my koi have parasites?

Because the majority of koi parasites are microscopic, you really don’t know if your koi have parasites unless you have a microscope. Two of the most common parasites you can see without a microscope are fish lice and anchor worm, the rest are microscopic.

Here are a few common symptoms that your koi will show if they have parasites.

Flashing: swimming fast and rubbing off the rocks, sides, and bottom of your pond
• Jumping out of the water (also could be poor water conditions)
• Scales missing on the sides of your fish from flashing
• Hanging around the water falls and surface (also could be a low oxygen level in your water)
• Yawning: trying to remove parasites from their gills

How do I treat for koi parasites?

Not all common koi parasites can be treated the same. To treat parasites you must divide them into three categories:

#1 Koi Flukes

Gill Flukes (egg layers) and Body Flukes (live bearers) are the number one Pond Keepers parasite problem.
Flukes dine on your koi’s blood by eating tiny holes through the “slime coat” of your koi. The “slime coat” covers the entire body of your fish to protect it from all the deadly bacteria (Aeromonas, Pseudomonas) your pond water.

When the flukes fall off the body of your koi, they leave a hole in the “slime coat” and that’s when the bacteria (Aeromonas, Pseudomonas) enters your koi’s body causing deadly Ulcers (open body sores) which are bacterial infections. Gill flukes can cause extreme damage to your koi’s gills, reducing their ability to breath

Fluke Treatments: The bad, and the best!

•Potassium Permanganate “PP”:

The Pros: it’s cheap!

The Cons: Very dangerous to use for you and your koi. Caution, wear protective eye wear and gloves. Do not inhale. PP will stain everything it comes in contact with, including you.
Attention: Keep away from children and pets. Make sure children do not have access to PP.

The effects PP can have on your koi if not properly treated can be very stressful. PP can cause damaged gills and even death. Make sure you follow all directions to the letter and add plenty of oxygen to your pond water while using PP. The more organics you have in your pond water the more PP you must use to be effective. The more PP you use the more stressful it is on your koi.
Note: does not do a very job on eliminating flukes.

*•Praziquantel “Aqua Prazi”

The Pros: Aqua Prazi is the safest treatment on the market for the treatment of gill and body flukes. Prazi is safer for you to handle than any other fluke treatment on the market. Prazi will not harm your koi’s gills or kill the lifesaving “Good Bacteria” in your filter. Prazi also has an added bonus by treating your koi for internal tape worms. Praziquantel is the gentle treatment of choice for treating gill and body flukes.

The Cons: When praziquantel was first used for treating gill flukes and body flukes it was very expensive.
Today the cost prazi is less than half of the old cost, however, still more expensive than the other fluke treatments on the market. The extra cost is well worth saving your koi from the stress and damage caused by cheaper treatments.

#2 Common Microscopic Parasites (MP)

Costia, Chilodincella, Epistylis, Ich, Trichodina: are a few of the most common microscopic parasites (MP) that can be deadly killers!

Some of these microscopic parasites can kill your koi very fast and must be treated ASAP. If your pond water quality is perfect and you are having many deaths every day, I would consider treating for microscopic parasites ASAP.

Microscopic Parasite (MP) Treatments: The Old and the New

• Salt

The Pros: It’s Cheap and a safe natural treatment

The Cons: Ten years ago these (MP) could be treated with plain salt with great results. However, because of the abuse (overuse) of salt there are now many salt resistant parasites. Instead of a 0.3% salt treatment, many koi breeders and pond keepers created “salt resistant” parasites by thinking more is better. Today we have Japanese koi breeders keeping their koi in a 0.9% salt treatment. Salt at a 0.3% level will kill your pond plants.
If you would like to treat your koi with salt here’s the instructions: Salt Treatment

The Pros: Terminate will treat all microscopic parasites plus, fungus infections. Total treatment just takes three days compared to weeks with a salt treatment. Terminate will not kill your pond plants or the good bacteria in your filter. Terminate an excellent treatment for treating microscopic parasites.
The Cons: Terminate is a strong treatment and should not be used on koi that are very ill.

#3 Fish Lice and Anchor Worm

Fish Lice and Anchor Worm are the only common parasites you can see on your koi without a microscope. If these two parasites enter your koi pond they will attack your koi no matter how healthy the koi are.

Fish lice puncture the skin of your koi in order to have a nice meal of blood. Fish Lice multiple very quickly laying over 500 eggs on the rocks and sides of your pond. In normal temperatures the eggs take a long four weeks to hatch. This is the reason any treatment must be at least 4 to 6 weeks. The hatched young will be eating on your koi for 6 weeks before you can see them.

Anchor Worm looks like a fine string with a (Y) at the end hanging from the body of your koi. This is a female that has her head buried in your koi having dinner and the two sides of the (Y) are her egg sacks containing hundreds of eggs. In warm water the eggs will hatch in app. 15 days.

Fish Lice and Anchor Worm Treatments:
• Dimlin or IDI

The Pros: Both are the best and safest treatment for fish lice and anchor worm
The Cons: Both these products are very hard to find on the market. However, there are other treatments on the market that are just as safe but take much longer treatment.
The best news is, you don’t see many koi that are infested with fish lice or anchor worm.

Conclusion: If you see signs of parasites on your koi treat them ASAP.
NEVER!! Add new Koi to your pond without treating them for parasites first.
The warmer your pond water the faster the parasites grow. In cooler water it takes much longer to kill them.