Fish staying on the bottom of the tank!!!

[captaincrash4]

My friend recently got 4 goldfish (I think the are common) and he has had them for about 2 weeks and today he rang me and asked why all of his fish are lying at the botton of the tank for quite?

I dont have alot of experience but i done water tests on it and the ammonia levels are 0 but nitrite and nitrate are sky high!! What can be done to help the fish as I'm guessing this is the reason they are all lying at the bottom?

Any ideas for the cause and ways to treat it would be great and i'll let you know hoe it all goes

Thanks

 

[black angel]

the tank is going through a cycle and the nitrite is now slowly turning to nitrate. nitrite is very toxic to fish and to help them through this he should dose the tank with aquarium salt to help them breathe.
He will need to get the salt level to .2%. To do this add 1 level teaspoon per gallon or 1 level tablespoon per 3 gallons (u.k or 5 for U.S) to get to .1%. the next day add the same again to get to .2%.
He should also do a few water changes before adding the salt to get the nitrite down to below 1.
As he changes the water he should add back the salt that he is taking out when he does regular water changes. So for example he takes out 5 gallons he needs to add 10 level teaspoons of salt to the tank. Its best to try and dissolve the salt before adding by dissolving it in a little boiled water first.
When the nitrite level gets to 0 for a while then he can stop adding the salt and do small water changes to get rid of it.