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Goldfish turning black!

Yossu

Yossu

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I have a goldfish, which was a regular orange (with a bit of white) colour when I bought it a few weeks ago. Last week, I noticed that it had a patch of back just in front of its dorsal fin. Over the past couple of days, it has developed black on the dorsal fin itself, as well as on its tail...

P1140656 (Medium).JPG


My poor photography, coupled with the fact that it wouldn't stay still means that you can't see it so clearly, but those patches are much darker than they look in the photo.

The fish seems healthy enough, swims around, chases after food, etc, but I'm a bit concerned that this is a sign of something wrong. The other fish seem fine.

Anyone able to advise? Thanks
 
There are two causes of black marks/ patches in goldfish.
1) Natural colouration that is starting to come through. This is genetic and there is nothing to worry about.

2) Chemical poisoning causes black patches on fish. The most common cause of chemical poisoning is chlorine or chloramine in tap water, and overdosing fish medications. You need to make sure any tap water is free of chlorine/ chloramine before it's added to an aquarium containing livestock. Never overdose fish medications.

Having said this, I am guessing this issue is simply natural colouration and nothing to worry about.
 
@Colin_T Thanks for the reply. It's not due to medications, as (thankfully) I haven't needed to add any. The tank has only been set up for a few weeks, and so far everyone seems OK.

I imagine our tap water has chlorine in, but I do treat the water when doing a water change.

Guess I'll wait and see. As I said, the fish seems seems healthy enough. Shame though, the black marks don't look very nice. Was a beautiful fish before this.
 
You can contact your water company by phone or online and ask them if you have chlorine or chloramine in the water. You can also ask them what the GH (general hardness) and KH (carbonate hardness) are.
 
Colin_T said:
You can contact your water company by phone or online and ask them if you have chlorine or chloramine in the water. You can also ask them what the GH (general hardness) and KH (carbonate hardness) are.
Click to expand...
I posted a screenshot of their web site in the beginning of this thread. Does that tell you?

MaloK said:
Do you have a test kit ? How is ammonia and nitrite ?
Click to expand...
Don't have any test kits yet. As far as I know, the tank is cycled and I do regular water changes, so I would be surprised if either of these was high. But yes, I do need to get some and check.

Thanks to both of you.
 
There is no ammonia mentioned in the water report and it says residual chlorine so theoretically you have chlorine in the water supply. And the water report says the water is soft. :)
 
Imo, its likely just color change. My common boy did the same thing as he grew and then eventually the color vanished.
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I also have another bought as a Moore though he was more copper colored as a baby, then turned black and now lost the black lol
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(He's technically a telescope eye goldfish instead of a Moore that he was sold as)
 
CassCats said:
I also have another bought as a Moore though he was more copper colored as a baby, then turned black and now lost the black lol

View attachment 346760

(He's technically a telescope eye goldfish instead of a Moore that he was sold as)
Click to expand...
They are the same fish, some call them moors and others call them telescope eyes.
 
Colin_T said:
They are the same fish, some call them moors and others call them telescope eyes.
Click to expand...
Moor (my phone likes to autocorrect it to Moore lol) is usually referred only to the black coloration however. Black is an unstable coloration already in goldfish, but black moors are the exception as it has been bred stable with them. They may technically be the same, but "moors" are normally referring to the black ones. There's a few variety of "telescope eye" goldfish--moors, panda moors, and celestial eyes.

So that is specifically what I am referring to in this case. He was sold as a "black moor". Which, he is not. He is literally the bare basic telescope eye instead of one of the specific "type" that are usually bred for.
 
TNG said:
When I was a kid, I had what I thought was a black moor. Imagine my disappointment when it slowly turned orange :(.
Click to expand...
Ha ha, just the opposite of mine! I bought it as an orange one, and was disappointed when it started turning black 😁
 
@CassCats Interesting. I wonder if that's what's happening to mine. Oh well, it seems healthy enough, so I'll keep an eye out and wait. You have some beautifully coloured fish there. If mine ends up looking as striking as those, I won't mind. At the moment, the black bits just look like it needs a bath!
 
Yossu said:
I posted a screenshot of their web site in the beginning of this thread. Does that tell you?


Don't have any test kits yet. As far as I know, the tank is cycled and I do regular water changes, so I would be surprised if either of these was high. But yes, I do need to get some and check.

Thanks to both of you.
Click to expand...
Not to be confrontational, but how could you know if a tank is cycled if you don't have a test kit?
 
sharkweek178 said:
Not to be confrontational, but how could you know if a tank is cycled if you don't have a test kit?
Click to expand...
Ha ha, I was waiting for someone to ask that! Not confrontational at all, perfectly reasonable question.

I should have rephrased it to say I'm pretty certain that the tank is cycled. How do I know? Well, the tank has been running for several years, and housed freshwater tropicals (angels, danios, guppies, usual stuff). Recently, we decided to rehouse the tropicals in another tank, and use this one for goldfish. I was careful not to clean the glass, and to be very gentle when cleaning the filter medium. That way, the bacteria on the glass and in the filter should have survived the transition. Also, the tank has been running four about four weeks now, so any further cycling needed should have finished.

Make sense, or did I get the wrong idea?
 
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