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. 

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