Parasites - Anchor Worms

Crustacean parasite, Lernaea - Anchor worm is a common parasite on our Koi which is clearly visible to the naked eye. The parasite burrows its head into the Koi's tissue, under a scale and only the body and tail are normally visible.

The juvenile stages settle in the gills of Koi, when they mature they mate and the male leaves the Koi, the fertilized female settles on the body of the Koi and continues to grow, becoming the familiar worm shape.

The female buries into the skin and underlying tissue to hold on. The damage caused can become a target for bacterial or fungal infection which can spread.

Lernaea lay eggs which can lay undetected in the pond and can hatch when conditions and water temperatures are right.

The parasite can cause serious damage to the koi where it penetrates the tissue. These wounds sometimes heal very slowly and if untreated become infected with bacteria and fungus, it is these secondary infections that cause the most risk to the koi.
To treat Anchor Worm you must treat the pond to sterilize the adults, this treatment should be repeated after seven days to ensure any eggs that were unhatched at the first treatment are now sterilized after hatching. Now all reproduction has been stopped. The treatment used is Dimilin.

Now the adults must all be removed from the koi. To do this you will need to sedate each koi individually and carefully remove the parasite with tweezers, making sure you remove the entire thing including the anchor part. Each entry wound should then topically treated. Check every koi in the pond to ensure none are missed.

1) Lethargy

Fish lethargy is caused by anaemia if fish lice have been attached long enough.

2) Haemorrhages

Haemorrhages, or blood pooling at the surface of the skin due to blood vessels bursting, can be found around sites where fish lice are or have been attached.

3) Paleness

Paleness, or a dulling in colour, is due to blood and nutrient loss from fish lice.

4) Flashing and Flicking

Flashing and Flicking behaviours are most often exhibited when fish are uncomfortable and are trying to alleviate their skin discomfort and pain.

5) Scale loss

Scale and skin loss is common when multiple fish lice have attached themselves.

6) Fin Erosion
If plagued by fish lice, you may notice your fish’s fins becoming tattered and decreasing in size as blood and nutrients are lost through parasitism.

7) Excessive Mucous

This response typically occurs toward the beginning of fish lice parasitism, as the fish’s body is trying to defend itself. However, many fish lice will simply just feed on this mucous.

8) Rubbing

Affected fish are likely to be seen rubbing against rocks, plants, and pond edges to try and rid the fish lice from their skin.

9) Secondary Infections

The longer that your fish have been infested, the more likely it is that they’ll develop secondary infections such as koi herpesvirus, larval nematodes, ich, and fungal infections. If you notice these symptoms, chances are that fish lice have been around for some time.


Treatment Recommended 

Treatment is by manual removal of the parasite with Tweezers under Anesthetic, ensuring that the whole parasite is removed. To be sure of complete removal, dip a cotton bud in strong Potassium Permanganate solution and dab the worm with this solution whereupon it will release its grip immediately. Pond treatments include Dimilin or Paradex. 
• Potassium Permanganate (PP) 1.5 grams per 220 gallons or 1.5ppm. Keeping the water purple for a minimum of 2 hours should effectively kill Lice. The general rule is to keep it purple for 4 hours, additional 1/4 or 1/2 doses may be required in ponds with heavy bio load. When water starts to go brown the PP is spent and not doing anything else. To neutralise PP either Hydrogen Peroxide (HP) or Sodium Thiosulphate (ST) can be used. Always add lots of extra air to a pond when treating with PP as it is an oxidising agent. Where possible avoid feeding for 24 hours prior to using PP. It is usually a good idea to do a deep clean of the filers and system to avoid having more organic matter in the pond for the PP to consume. 

• Salt Remember NOT to use salt if Formalin or PP is in the pond already. Use an accurate salt meter to ensure the percentage or ppt is safe. 0.3% starting dose to slowly increase to 0.6% over 24 hours. Any further salt increases should be done slowly. *Remove any Zeolite from the filters as the salt will release ammonia from it. Keeping on top of pond and filter maintenance will help reduce the occurrences. 
Any treatments added are done so at your own risk. It is your responsibility to know your pond volume and to calculate dosages correctly. 

Golden Rules Of Treating Koi

Scrape the Koi first before treatment

Identify which Parasite is causing the problem before treatment

Make sure the pond water is salt-free because it can harm Koi when used with most chemicals

> Calculate the Volume of Water accurately

Turn off the UV Unit when treating your Pond

Test your Water Parameters before Treatment

> Follow the label’s instructions and do not overdose. Chemicals can cause serious damage to your Koi if amounts are miscalculated