HELP! My fish are sick

[kelltoria]

I am having major problems with my freshwater tank. I keep goldfish and without going into too much detail, I had to completely change all the water in the tank about 3 weeks ago as a result of which I killed all the bacteria in the gravel and am having to wait for the tank to cycle. Unfortunatly I have had to put my fish back in this tank as they have no where else to live.

The water was VERY cloudy. I have been told that this is ammonia or nitrite in the water which is building up a result of the undergravel filter not working yet. In order to counteract this build up I have been changing about 1/4 of the water in the tank approx. every 4 days (or when the water goes really cloudy). This has been helping and the water seems to be clearing.

Although I thought I was wining the battle NOW some of my fish are sick. One fish has blood in its fins and darts about frantically apart from when it is hanging about around the top of the tank. All it`s fins are looking quite ragged and it keeps them clamped close to it`s body.

Another fish has what appears to be silver / grey patches on its head and back (as if it`s been dusted with icing sugar). It also keeps its fins clamped close to it`s body and the ends of some of it`s fins seem to be black. It also either hangs around the top of the tank or stays near the bottom in a corner.

I have visited several pet shops in an effort to get some medication for the fish but so far they have diagnosed different diseases such as velvet / fin rot / bacterial infection/ fungus infection etc (one said that the symtoms were all just indicative of poor water quality and to leave the tank alone). Please help me help my fish!! If anyone knows what is wrong with them OR what is likely to be wrong with them please let me know ASAP.

Thanks, Kell

NOTE: The only one of my fish that is not sick is one I won at a local fair and carried home in a plastic bag!!!

???

[clothahump]

Leave the tank alone to finish cycling,it sounds like you have a classic case of new tank syndrome. You can help this by purchasing some Bacterlife or similar beneficial bacteria in a bottle.
Add a small amount of salt,one teaspoon per gallon until things settle down, when every thing is stable start making small regular water changes with out the salt.
(Salt lowers the toxicity of nitrite.) ???

[kelltoria]

Do I just put rock salt in?  Or do I have to buy proper marine salt from a pet shop. Or could I use sea salt that you put in a salt mill I dont want to make them worse.  

[clothahump]

Sea salt from a mill is adequate for the job.
This is used by dealers to get nitrite levels down. 8)

[Matt Nace]

What size tank is this? What kinda of goldfish are they? Comets?
Do you have anything other than the Undergravel filter for mechanical filtration?

on a side note, are you the one with the fish tank in a college dorm?

Do you have test kits? Ammonia, Nitite, nitrate?