What is ich or

whitespot
All of us at one time or another will find ourselves confronted by the dreaded ich or whitespot, it is unfortunately a very common part of being involved in the fish keeping hobby, in fact it is the most common ailment that affects our hobby. Understanding the problem and knowing how to treat it can make fish keeping a great deal easier and less painful both to the fish and your heartstrings.

• What is ich or whitespot
  Ichthyophthirius multifilis is a protozoan parasite which uses fish as its host, (no fish means no whitespot and a very boring tank). The ich parasite has a 3 stage lifecycle, one part on the fish , one in the substrate and one part free swimming.
  The free swimming stage of the ich is called a tomite, this is the infectious stage of the parasite. At a water temperature of 25C the tomite must find a host fish within 48 hours to survive or it will die. Once the tomite finds a host it will burrow under the scales and skin of the fish.
  After the parasite has entered its host it is called a trophont, this is the stage which is visible as the classic whitespots on the fish,giving the appearance that the fish has been covered with salt or sugar grains. The trophont is constantly moving in a tumbling motion and feeds on the cells and fluids under the skin. When the trophont is mature it forces its way out of the fish and falls to the substrate. A mature trophont can measure up to 1 mm in size.
  Upon reaching the substrate the parasite, now called a tomont, forms a capsule around itself and starts to divide. A single tomont capsule may contain up to 1000 tomites prior to hatching. When the capsule hatches the tomites will again be free swimming and in search of a host.
  The lifecycle of the parasite is temperature dependent, at a temperature of 10C deg the lifecycle will take 6 or more weeks to complete, while at 28C deg the lifecycle will complete in about 3 to 4 days.
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  How to recognize a fish with ich
  A fish which is infected with the ich parasite will usually give its first signs of infection by scratching against objects in the tank such as ornaments, filters, gravel and anything else in the tank that it can find. Usually one fish will start and others will follow over a number of days as the parasite multiplies in the tank and infects more and more fish. after the scratching starts the next sign will be the classic salt or sugar looking grains on either the skin or the gills of the fish. If the infection is in the gills the area will appear pale and swollen. In the later stages of infection the fish will become lethargic and will eventually die. Death of the fish could be caused either from the damage inflicted by the ich itself or by a secondery infection caused by the damage done by the ich.
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  How to treat fish with ich
  Because the parasite is present in the substrate as well as on the fish it is impractical to isolate the fish for treatment, the entire tank and its contents must be treated to get a satisfactory outcome. There are a large number of commercially available treatments for whitespot, many of them based on formaldehyde, malachite green or methylene Blue or combinations of these chemicals. As well as the chemical treatment it is also possible to treat ich with salt, and also by heating the water in the tank to a level at which the parasite cannot survive. All of these methods of control will work but all of them can present a very real danger to some or all of the fish, plants and bacteria in your tank.The easiest method, but possibly most dangerous to your fish, is the gradual heating of the water to a temperature at which the parasite dies. While the parasites lifecycle is at its fastest at about 28C deg, a temperature of 30C deg is enough to kill them, unfortunately this temperature is also enough to kill a lot of fish. Tanganyikan fish cannot handle these temperatures but mbuna can. To use this method you will need to check the heat tolerance of the fish species in your tank. The temperature would only need to be maintained for about 5 to 7 days, as the lifecycle of the parasite would only be about 3 or 4 days. If using heat as a treatment for ich or even if using heat to speed up the ich cycle for another method of treatment it is important to remember that a rise in water temperature will decrease the waters ability to sustain oxygen so extra aeration is essential to maintain oxygen in the water.Salt is another relatively easy method of treating ich. For salt to be effective it needs to be in concentrations of about 0.05 % which would be approximately 500 grams to 100 liters of water. These levels of salt would be fatal to a lot of fish so check the salt tolerance of the species in your tank. If using this method it is important to use non iodised salt. Aquarium salt or common salt can be used and the concentration of salt in the tank should be built up over about 3 days to the desired level so as not to shock the fish too much. Salt can also damage a lot of aquarium plants. To be effective this method should be used for at least 10 to 14 days with the correct concentration of salt being maintained with water changes done about every 3 days.

  Commercial remedies require accurate measuring to ensure that you do not overdose or underdose the treatment. As with the other methods of treatment, some of these treatments present dangers to some fish, such as scaleless fish, loaches etc. Some commercial remedies are also fatal to the bacteria colony in your tank and could cause an ammonia spike if not monitored closely. There are usually directions on the bottle to tell you which fish are in danger and also to tell you how often to remedicate. If the bottle says to remedicate every 3 days then do a water change prior to re medicating, and again maintain treatment for at least 10 to 14 days. It is important to maintain treatment till all parasites have been killed as if this is not done we run the risk of breeding medication tolerant parasites, which would make eradication in future even more difficult.

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  Disclaimer
  While every effort has been made to give accurate and useful information, it is up to you to decide what is appropriate for your fish and your circumstances, and some or all of the information given here may be inappropriate for your fish and/or circumstances.
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  References and further reading:http://www.fishdoc.co.uk/disease/whitespot.htm
  
  http://www.thetropicaltank.co.uk/hdwspot.htm
  
  http://edis.ifas.ufl.edu/BODY_FA006

canerodATbigpond.net.au