Argulus Koi Parasite

Argulus (Fish Lice)  parasites for koi fish can be commonly introduced into koi ponds by frogs and toads. Argulus (aka Fish Lice) are more developed than most of the other parasites. You can see them quite well without using a microscope. They move around and itch the fish and cause complications that can kill koi and goldfish.



It is however easy to detect with the naked eye especially against the background of fins and white skin of affected koi fish. Size varies from between 1mm and 5mm. Attaching themselves to the koi by suckers which damages the skin, they also inject a poison into the body of the koi which causes inflammation, bleeding and potentially secondary bacterial infection. Pale green in colour, juveniles are more transparent.

Argulus must be eradicated quickly as the parasite causes considerable physical damage to the skin which often results in subsequent ulceration of the affected areas if left untreated.

How to Recognize, Treat and Prevent Argulus in Your Koi Pond

All you must do is get close to the fish to see these little creatures. And - creatures is probably a good word for them because they are so well developed with legs and what looks like a type of skeleton. Like most parasites Argulus is easy to get rid of if you treat the pond with the right stuff.

Recognizing Argulus

You can't mistake Argulus. They look like tiny see-through, jelly-filled, little creatures with several pairs of legs and a tail. They are only about 1/4 inch long and tend to take on a green tint. Basically, if you see a small round thing that has visible legs and almost invisible body around it your fish have lice!

Argulus Koi Parasite, Pic From www.pondcare.com

Treating Argulus

It's very simple to treat. We suggest using ProForm LA, Fluke Tabs or Anti-Fluke. ProForm LA is best to use if it's cold when treating because it works in lower temperatures though it also works fine during summer. Fluke Tabs are easier to use for quarantine tanks because each tab treats 100 gallons. Anti-Fluke (which is part of our Parasite Pak) is best used in warmer weather.

Salt will do nothing for argulus. It doesn't hurt to perform a salt treatment along with any of the treatments described above because it will encourage the fish's natural protective slime layer to form and it won't have any interactions with the medications.

You will need to have de-chlorinator on hand (if you use chlorinated water) because some water changes will be necessary.

Emergency Procedures

Treat the whole pond with either ProForm LA, Anti-Fluke or Fluke Tabs.
For added benefits, perform a salt treatment while treating for anchor worm.

What to Expect Next

Secondary conditions are not uncommon with argulus because it makes holes in the skin of the koi or goldfish for bacteria to invade. This often leads to ulcers which will need to be treated as they are noticed.

Preventing Argulus

Quarantining and treating any new koi or goldfish is the key to preventing any infestation of argulus.


Source:
http://www.ponddoc.com/koihospital/Diagnostic/Parasitic/Argulus.htm
http://www.koicarp.org.uk/koi_parasites.htm