"Ich"  (aka Ichthyopthirius multifiliis)

Ich is one of the most recognized parasites in the world of ponds and aquariums.  Freshwater fish (including our own goldfish and koi) have their own "brand" of ich while there is also a saltwater ich as well.  We are only concerned, however, with freshwater ich that affects koi and goldfish in our ornamental ponds.  Ich will kill the fish if it goes too far.

How to Recognize, Treat and Prevent Ich in Your Koi or Goldfish Pond

Most parasites that affect koi and goldfish cannot be seen with the naked eye.  Ich is one that we hope we can't see because when we actually can see it without the use of a microscope it has progressed quite far in its infestation.  Under the microscope ich looks very similar to the drawing above.  It is round and has a boomerang shaped object in the center.  Unless you have super-human eyesight you can't see this ich without placing a mucus scraping under a microscope. 

Recognizing Ich

For some reason, ich seems to target goldfish more than koi although koi can certainly have it and spread it as well as goldfish.  If you look at freshwater tropical fish at the pet stores a lot of times you'll see white specks on the fins of the fish.  This is ich.

Once the ich has been around for a while and has done some damage it will get to the point that we can see it without a microscope.  It looks like a sprinkling of salt on the fins and flesh of the fish and you'll see it often on the fins of a fish when the fish is suffering from fin rot.  And - we can thank the ich for contributing to the fin rot.  Ich is also called "White Spot" because that's exactly what it will look like in the latter stages of its development.

The trick, however, is to catch ich before it gets to this stage.  These little rascals, like all koi and goldfish parasites, are active and will tickle the fish as they dart around on the skin.  The fish will scratch themselves as best as they can, taking a "running" jump and scraping against the walls and floor of the pond to relieve the itch.  We call this "flashing". Other behavior the koi may exhibit is spastic swimming or spiraling, even jumping. 

The only sure-fire way of diagnosing ich is to do a mucus scraping on the suspect fish.  It's quite interesting and, if you can get your hands on a microscope, quite easy as well.  When looking under the microscope if you find anything that moves on its own chances are it is a parasite and, if it looks like the drawing above, it is ich. 

Treating Ich

Treating for ich is the easy part!  Salt will kill ich but it has to be in a strong enough dose. 3 lbs. of non-iodized salt per 100 gallons (yes, that's the amount!) will kill ich.  The salt must stay in the water for at least 2 weeks so that it will kill any baby ich as well.  We have a very pure salt that we use on our own guys that is wonderful to use for treating ich.

Salt in that high of a dose will kill or retard the growth of many water plants so often a salt treatment is more trouble than it's worth.  For planted water gardens and koi or goldfish ponds that have plants we suggest you use either ProForm C or QuickCure.  If your water temperature is not very warm you should use the ProForm C.  You can use Quick Cure in spring or summer but not when the water is cold.  Quick Cure is part of our Parasite Pak that addresses flukes, fish lice and anchor worm as well as ich and other parasites that salt will kill.

You may need to change most of or a portion of the water when treating for parasites.  Make sure to have de-chlorinator on hand.

Emergency Procedures

1. Perform a salt treatment or treat with ProForm C or QuickCure.

What to Expect Next

Once ich is eradicated from your pond you should not have any residual affect from either the ich or the treatment except maybe that the fish have been stressed so that they are susceptible to anything that may come along.  Just be "gentle" with the fish for a while and keep an eye out for ulcers or other problems that arise when fish are stressed.

Preventing Ich

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

More Information About Ich

• Buyer Beware - The Importance of Quarantine
• Flash Dance - A Closer Look at Parasites

Items You Might Need:

Doc's Pure Salt

Parasite Pak

ProForm C

Doc's De-Chlorinator

Know Your Gallons!

Heavy Duty Water Meter

© copyright, 2008, PondDoc.com.  Reproduction or use of any content on this website prohibited without written consent from PondDoc.com.  This advice is given free of charge and serves as information only to help you with determining the cause of fish health problems.  The content given is to be used as guidelines only.  By following the guidelines on our website you are agreeing that we will not be held responsible or liable for any losses.  We cannot diagnose your specific case.  We are simply forwarding the benefit of our extensive experience with koi and goldfish health.