[cubpaw]

I have two goldfish, everything has been fine until the other day when I saw a greenish disk shaped parasite stuck to the top of ones head! He didnt even seem to know it was there and was swimming around happily. I took him out with a net and quickly plucked the parasite off his head with tweezers and put him back. The next day I noticed another one on the other goldfishes tail and I tweezed that off as well. Then there was a third- so I did a complete water change and washed everything in the tank off very well (no soap but I let the tank sit with hot water and salt and I rinsed the gravel out very well in a strainer) I put the two fish in a small bowl with some salt after reading on a website that a salt dip might help kill the remaining parasites and would not harm the fish if administered in the right doses. I also put some salt into the new tank water as the website said, one teaspoon per gallon I believe. As soon as I put the goldfish back into their tank one of them went directly to the bottom and has been there for two days now! He will swim if disturbed and sometimes will seem to snap out of it for 5 minutes or so and be normal, but otherwise looks as though he is completely dead. Now he wont come to the top for food so I put some thawed frozen peas without the skin into the tank since I read that if he is constipated or has swim bladder problems this may clear it up. Also the peas sink so hopefully he will just eat them off the bottom. I also put Copper Safe in the tank (one teaspoon per 4 gallons) this is what the guy at the pet store told me to do to clear up the parasites. There appears to be no more parasites, the other fish is as happy as can be, but my little guy seems to be so sick and I dont want him to die. Please help!

[brad]

First, it does not appear that your fish have Chilodonella, which is good nwes since this is a difficult parasite to treat. What they do appear to have is Argulus (fish lice). Not uncommon on goldfish. Salt will usually kill the parasite but if they persist, you can try Clout or a similar medication. CopperSafe, while it will eventually kill the parasites, is not the best thing for the fish, and I would not have advised its use. If left in the tank too long, there is the risk of liver and gill damage occuring.
Since you have completely broken down the tank (not really necessary since the medication would have killed the parasites), please check for both ammonia and, more importantly, nitrite. Nitrite in fershwater can he highly toxic, so do water changes if the level rises.
Is the one fish still sitting on the bottom?