Koi Parasites
Most koi parasites are not visible to the naked human eye and in order to correctly identify any koi parasites you will need a microscope with a magnification of at least 400 times, JoSo Products have one of these in store and offer a full Koi Parasite scrape and parasite identification service, We also sell suitable microscopes so you can perform your own future scrapes and diagnoses
- To accurately detect any koi parasite causing an infestation of your koi, we will need to take a skin scrape from an infected fish this involves using a microscope slide to carefully remove a small quantity of mucus from the koi, The mucus is then sandwiched between the slide and a cover slip and inspected through the microscope
- If you suspect you have a koi parasite problem, skin scrapes need only be taken from two or three koi and if parasites are found, it is safe to assume all koi are infested by the parasite and therefore the entire pond will require treatment
- Before any parasite treatment is used in your koi pond, it is vital that you know the exact volume of water and temperature, and that adequate filtration and airation is provided, Parasite treatments will lower the dissolved oxygen levels in the pond so we recommend adding additional airation when using any chemicals in your koi pond. You must also switch off any ultra violet sterilisers / clarifiers and ozone equipment
Trichodina
- Is one of the easiest protozoan parasites to detect under the microscope as it is almost perfectly round with hundreds of hooks which resemble cilia found its periphery and it constantly rotates as it moves through the mucus, causing tissues damage.
- It attacks both skin and gill tissues of our Koi, and can often cause more damage to gills than realized.Classed as a warm water parasite, it can survive for some time without a host. It causes vegetation of the skin giving rise to a grey white opaque appearance on the body of infected Koi which exhibit the classic symptoms of flashing, rubbing and lethargy.
- Trichodina is another small protozoan parasite which is commonly found on koi. Microscope identification is necessary, as it has an average size of 0.07mm in diameter.
- This parasite is circular in appearance, and is often seen spinning and moving very quickly when viewed through the microscope. The parasite attaches to the koi using tiny hooks and holding discs.
- The koi parasite Trichodina can quickly cause severe damage to the skin of a koi (as can all parasites) leaving the koi open to secondary infection from bacteria such as Aeromonas.
- Trichodina can swim well and therefore this koi parasite can quickly infest an entire pond of koi, especially when the stocking level of koi is high. Trichodina multiplies by division.
Dactylogyrus/Gill Fluke
- This koi parasite is very similar to Gyrodactylus in appearance, it has a set of hooks with which to attach itself to the host koi and these are surrounded by a number of smaller hooksThe two parasites differ however in their method of reproduction, this koi parasite is an egg layer, and can lay up to two– dozen eggs per hour. Water temperature is important as the reproductive rate increases in warmer water, and decreases in colder water. The same applies to the time required for the eggs to hatch
- In warmer water hatching can take only four days, whilst in colder water it may take as long as thirty days. This is a very important fact to remember when treating this koi parasite as most treatments will not kill the eggs, and they can hatch even after treatment and re-infect the fish
- For this reason either the initial treatment has to stay active for at least four days, or you must do a second dose of the treatment.
Gyrodactylus/Skin fluke
- Gyrodactylus is one of two common worm type parasites which the koi keeper may encounter, the parasite is worm like in shape and it has hooks with which the parasite attaches itself to the koi, this koi parasite reproduces live young being hermaphrodites, all of the adults are capable of producing young, and each one will carry a single larval parasite in its abdomen,
- turther more this unborn parasite is also developing a larval parasite in its abdomen before they are even born, and in as little as one day after being born, those young can also give birth, So it’s easy to see that this koi parasite is very prolific, and one individual is capable of reproducing into thousands in a short period of time
- When viewing this parasite under a microscope you can often see 3 or 4 developing parasites within each other
- Once this parasite is attached to a host koi, it lives and feeds on the mucus skin and blood of the koi. The parasite is capable of surviving without a host koi for five days.
White Spot
- The white spots on the skin, gills and fins are individual protozoan cells that are under the skin and feed on the body fluids and cells, they then punch out of the skin and fall to the bottom of the pond collect together and begin breeding, the offspring then re-invest the fish, white spots symptoms are scratching and swimming into the water inlet, failure to feed and lethargy, It is fatal if untreated, fortunately commercial white spot remedies are widely available
- Classed as a large protozoan parasite, white spot must initially be detected through the use of a microscope, however if left, its effects becomes identifiable with the naked eye, Koi infected by white spot appear to be covered in white spots the size of salt grains, where the parasite has burrowed through the outer skin layer
- To multiply the adult parasite leaves the host koi, it then forms a capsule around itself Within the capsule it divides and multiplies producing up to 1000 tomites (babies) These are then released as free swimming parasites to go in search of a new host koi
- This reproductive cycle is rapid and so early detection of this koi parasite is essential.
Argulus
- Argulus is a type of crustacean, the parasite attaches to koi using suckers. The parasite then punctures the skin of the koi and feeds on blood and body fluids. It also releases a toxin when it punctures the koi, this toxin may cause erratic behavior of the koi as the effects cause intense irritation, the punctured areas of the koi will also be open to secondary bacterial infection, this parasite can be introduced to the koi pond by visiting frogs and toads.
- Argulus reproduce by laying eggs, After mating the female detaches from the host koi to deposit her fertilized eggs on the pond walls or any other surface, Upto 500 eggs may be laid, dependent on water temperature the eggs take between two and four weeks to hatch, the newly hatched parasites will swim to find a host koi, they will reach sexual maturity after 20 to 50 days depending again on the water temperature of the pond then the cycle starts again.
- To treat an Argulus outbreak you will need to sedate and inspect every koi in the pond, removing all adult parasites with tweezers, the pond must then be treated to kill off the juveniles, this treatment should be repeated two or three times at intervals of seven to ten days,
the most effective treatment is Masoten.
