Question
QUESTION: I have three new goldfish (ryukin, commet and oranda). I have been monitoring the Ammonia, Nitrites and Nitrates as my tank didn't cycle prior to the fish being introduced. Ammonia has stayed below .5, nitrites have only just appeared and are at .25. Nitrates are just registering. I have been making daily 10% water changes and every third day i make a 30% water change. I make sure I put water conditioner in the new water and just a small amount of aquarium salt. I have also been using a bacteria supplement to facilitate the commencement of cycling. I also reduced feeding to once every 2 days and pH is neutral. I bought new plants from the pet shop today and about an hour after i put them in my fish developed white spot. I went straight to the pet shop and got medication which i promptly put in the tank (and removed my carbon filter). My question then is what have i done wrong, what can i do to help my fish and what can i do in the future to avoid this.

ANSWER: It sounds like you are doing a good job for the fish.  How big is your tank?  Are you sure they have ick?  You can send me photos of the fish via my web site if you want my opinion on that.  I use aquarium salt at a tablespoon per 3 gallons and Aquari-Sol to kill ick.  If caught early, ick is usually easy to treat.  

You want your tank to cycle but you also don't want to over stress the fish.  So, it's a hard balance of deciding whether or not to do water changes and how much.  How much I would recommend depends on your tank volume.  If it's say 20 gallons and the fish are under 2 inches, then doing a 30% water change a few times a week may be enough.  The good bacteria need the ammonia to grow so you want to let them have some but at the same time not overexpose the goldfish to the ammonia.  My page on water chemistry is at http://www.fishpondinfo.com/chem.htm
The page could use a lot more information and details (after all, I'm a chemist) but my time available to work on my site is less and less every month.

If you added water from another aquarium (water with a plant from the store), that could have carried ick in it.  Usually, it would take a few days for them to get an active infection as a result.  How many days did you have the goldfish before the ick appeared?  If it hasn't been long, they may have been carrying it all along.  

In the future, rinse off any new plants and never add store water to your tank (that goes for added fish too).  If you want to go a step further, you can sterilize new live plants with potassium permanganate solutions or other chemicals.  It's usually not necessary.  I used to do that to my pond plants to avoid adding snails to my pond but they ended up there anyway so it was a lot of extra work for nothing.

Good luck!

---------- FOLLOW-UP ----------

QUESTION: My three goldfish suffered an outbreak of whitespot/Ich last Thursday (i.e. the parasite had reached maturity as I could finally see it on their Caudal and Pectoral fins. I immediately commenced treatment using a popular three day medication. I spoke with a number of aquarists including the one who sold me the fish.
 
I followed the instructions for three days but then spoke to another aquarist who told me that she does the following:
Day 1: full dose
Day 2: half dose
Day 3: 1/4 dose
Day 4: full dose
 
And so on for the next 10-14 days. I started to do this but then began to worry about the adverse effects on my fish so went back to once every three days. In between treatments I did partial water changes. On about Tuesday the spots were starting to burst and two of the fish had no spots at all. Then this morning when I went to give them the full dose low and behold two of the fish have new spots! I don't understand what I have done wrong. I am petrified that this second bout will kill them. There is no ammonia or nitrite (but as I didn't get a chance to let the tank cycle before the fish were placed in it I expect a spike - although the tank is two weeks old).
 
Please, am I doing something wrong?! What do you recommend I do now. I am open to any suggestions.  

Answer
What is the active ingredient in the ick medication that you are using?  In general, when a course of treatment is followed, water changes are only needed before it's started and after it's done.  The medication is meant to accumulate some.  Did you add aquarium salt as well (I see you added a "small amount.")?  It can help.  Try a tablespoon per 3 gallons.  Also, raising the temperature will speed up the ick life cycle which I'm sure you already know.  You sound very educated already.  If your current ick medication is not working, it might work to do a partial water change and switch to a different medication (with a different chemical).  Ick is usually easy to cure; there must be a lot in your tank.  I hope things improve!