Goldfish changing colour

We got an aquarium 6 month ago which is populated by 8 goldfish. My wife
noticed yesterday that one of the fish, normally a golden brassy colour has
developed 2 larger dark/black spots on the top. He seems to be happy enough
otherwise, but my wife is worried it is some kind of disease.

The water is changed regularly, we test Ph and the aquarium is clean - so it
looks like a healthy environment to me.

Any advice or opinion?

Cheers, Oscar

Black marks appearing like this are usually caused by ammonia burns. Water
quality cannot be determined by simply looking at it. You need to test for
ammonia, nitrite and nitrate a.s.a.p. If you don't have the kits, buying
them is a good investment, or alternatively, take a sample of your water to
your local fish shop who will test it for you. Take a pen and paper and
write the exact results down so you can post them here as most advice given
by employees in these places is terrible (unless you are really lucky!). if
you post the results we'll try to help you.
Until then start daily 30% water changes (using dechlorinated and
temperature matched water). This will dilute any toxins in the water and
make things better for your fish.
Mel.

"Oscar" wrote in message
...
We got an aquarium 6 month ago which is populated by 8 goldfish. My wife
noticed yesterday that one of the fish, normally a golden brassy colour
has
developed 2 larger dark/black spots on the top. He seems to be happy
enough
otherwise, but my wife is worried it is some kind of disease.

The water is changed regularly, we test Ph and the aquarium is clean - so
it
looks like a healthy environment to me.

Any advice or opinion?

Cheers, Oscar

Oscar wrote:
We got an aquarium 6 month ago which is populated by 8 goldfish. My wife
noticed yesterday that one of the fish, normally a golden brassy colour has
developed 2 larger dark/black spots on the top. He seems to be happy enough
otherwise, but my wife is worried it is some kind of disease.

The water is changed regularly, we test Ph and the aquarium is clean - so it
looks like a healthy environment to me.

Any advice or opinion?

Cheers, Oscar


If it seems healthy, its probably maturing, and his colors will change.
thats what happened to my fish, the black goes down the top to the tail.
Mine went from a brassy to a beautiful light orange.

Kay

The black is caused by healing from ammonia burns as well. A fish which has
had an injury or other condition, like ammonia burn, will turn black in that
area as it heals, and it will return to normal in a week or 2.

I do agree that you should test the water since 8 fish should be in a rather
large tank (at least 10g per adult fish, adjust for size/age). I would
think your fish is healing from a previous condition so you are doing
something right. Keep up the partial water changes and keep an eye on the
water by using test kits - ammonia, nitrite, nitrAte.

We got an aquarium 6 month ago which is populated by 8 goldfish.

How many gallons is the tank?