I got a gold goldfish 3 days ago and now strange black spots are appearing all over it's body?

Question

Okay, so I won a goldfish at a carnvial three days ago and put it in my 30 gallon tank with a bunch of other fish, it was perfectly gold until the other day when I realized it was getting black spots all over it's tail, fins, and scales, what is happening, is it from stress? Is it from a chemical? (May I meantion that it happened after I put in 30 times the amount of cleansing chemicals to clean your fish tank water, I thought it read 1 millileter, but it actually read 10 millileters, and I did that three times, ) is that what is causing it? HELP!

Answer 1

maby ammonia burns

carnival goldfish need 50 gallons minimum

Answer 2

Black dots usually indicates black ich and needs to be treated as such.

However, are these splotches or small pin head dots?  Bloches could be healing marks from ammonia burns.

Have you tested the water in your tank.

Dumping this much water conditioner in the tank isn't a good thing.  Do a water change to help remove this from the tank.

Also, the only time you add water conditioner is when you do a water change.  It does nothing for the fish anyother time.  Always add it to the bucket in which you are adding to the tank, never directly into the tank.

Is he or any of the other fish showing any signs of stress?  Goldfish like colder water (below 75)  That could be another problem.  What fish are he with?