Why do goldfish change color?

Have you looked at your goldfish recently and thought that it looked a different color?

Have you compared old photos of your goldfish to now and noticed that your fish’s color used to be brighter?

You may even have noticed your goldfish gradually turning white!

Don’t worry, you’re not going crazy! It’s actually perfectly normal for goldfish to change color over the course of their lives.

(Ok, maybe not quite as much as in the picture! If your goldfish goes that color then consult a vet!) 

Read on to find out why goldfish change color…

Takeaways:

  1. Goldfish Color Changes Are Normal: Goldfish can change color as they age, with young goldfish being brown and gradually developing their adult color over time.
  2. Factors Influencing Color:
    • Maturation: As goldfish grow, they change color naturally.
    • Diet: Some foods can enhance goldfish coloration.
    • Sunlight: Goldfish kept in well-lit environments tend to have brighter colors.
    • Water Quality: Poor water conditions can cause goldfish color to fade.
    • Illness: Health issues can impact a goldfish’s color.
    • Genetics: Some goldfish are genetically programmed to change color as they age.
  3. When to Be Concerned: A gradual color change is typically nothing to worry about. However, if color changes suddenly or is localized (e.g., small white spots), it could indicate illness, and a vet should be consulted.

Has your goldfish changed color?

The main reasons that your goldfish may have changed color are:

  • Maturing to adulthood – goldfish are actually brown when they’re born, and develop their adult color later!
  • Diet – some goldfish foods bring out color in goldfish more than others
  • Amount of sunlight – goldfish in a pond or an aquarium that gets some sunlight will be more brightly colored than goldfish kept in darker conditions
  • Poor water quality – you should get a test kit that measures ammonia pH, nitrite and nitrate. Make sure that you’re using a suitable aquarium filter and doing enough water changes, as poor quality water can make goldfish color fade (and is bad for your fish’s health of course!)
  • Illness or disease – again, check your water quality and look for other symptoms of disease
  • Genetics – some goldfish change color as they age, simply because goldfish can live a very long time and that’s what their genes program them to do!

If your water quality is good and your fish is getting enough sunlight, then don’t worry about any gradual change in your goldfish’s color. Your fish could be changing color for any of the above reasons, or perhaps other reasons, and it’s almost certainly nothing to worry about.

However, if you notice your fish change color very suddenly, or only in localized areas of their body (small white spots for example) then you should consult a vet or search for the symptoms online. It’s possible that your fish could have a disease such as “Ich” (also known as “white spot disease“).

FAQ’s:

1. Why is my goldfish changing color?
Goldfish can change color due to maturing, diet, sunlight exposure, water quality, illness, or genetics. It’s usually a natural process unless accompanied by other symptoms.

2. Does poor water quality affect my goldfish’s color?
Yes, poor water quality can cause goldfish color to fade. Regular water testing and maintenance are important to maintain both fish health and color vibrancy.

3. Can goldfish change color as they age?
Yes, goldfish typically change color as they grow. They are brown when born and gradually develop their adult color as they mature.

4. Should I be concerned if my goldfish changes color suddenly?
If the color change is sudden or localized (like small white spots), it could indicate illness, and you should consult a vet. It may be a sign of diseases like “Ich” (white spot disease).

5. How can I enhance my goldfish’s color?
Provide a balanced diet, ensure good water quality, and make sure your goldfish gets enough sunlight to help bring out its natural colors.

6. Can diet affect my goldfish’s color?
Yes, certain goldfish foods can enhance their color, making them more vibrant.

11 thoughts on “Why do goldfish change color?”

  1. Hello,
    I’ve noticed reddish spots on my common goldfish’s tail. Can you tell me what this may be? Ammonia levels and ph are In a healthy zone.
    Thank you!

    Reply
    • Hi Jessica. Sorry to hear this about your fish! It could be a bacterial infection. Does it look like this?

      When you say “ammonia is in a healthy zone” do you mean zero? We would suggest that ammonia should be zero in a well cycled tank and anything above that – even low levels – would be a concern and could either harm your fish or let bacterial infection take hold.

      Reply
  2. Hi,
    I have 2 golfishes. But only one of them changes its color to black and only in specific areas. I just bought them 3 days ago. The other one doesn’t change color at all. Is it something to worry about?

    Reply
    • Hi Shifa, thanks for your comment,
      You should do a water test to see if there is anything wrong with the tank which could cause any problems, if this is fine, and the goldfish are eating, swimming around and otherwise look healthy, it is probably nothing to worry about, goldfish often change colour throughout their lives, and actually most goldfish start out completely black when first hatched.
      If there is something wrong with the water, perform a water change, or if you do suspect a disease, here is some help with identifying it: https://thegoldfishtank.com/goldfish-info/diseases/goldfish-fungus-types-of-fungus-causes-and-treatments/
      hope this helps.

      Reply
  3. Hi,

    My goldfish was a dirty silver/gold with black patches on it back.
    We’ve gone away for 4 days and the fish is now completely a bright golden colour with a slight black on its fin.
    My mum has been taking care of them whilst we were away.
    Is this possible or is it a new fish?

    Reply
    • Hi Kerri, thanks for your comment,

      Yes it is entirely possible for goldfish to change colour, this is especially true with younger fish less than 4″ long.

      However, this change is normally gradual, and usually takes weeks to change colour completely.
      The fish may also just be washed out from stress, you may need to do a water change.
      Give it a day or two and test the water to make sure it is okay, you might find it changes back to its original colour, after it has settled down.

      Look for other features you may recognize in your fish, like the shape of the fins, size and behaviour, if it is completely different from what you remember then your suspicion may be correct.
      perhaps an interrogation is in order!

      Reply
    • Hi Alina,
      sounds like a normal occurrence, but keep an eye out for any other signs of ill health just in case

      Reply
  4. I noticed my goldfish who is gold turning red one side of the body and a little underneath should I be worried?

    Reply
    • Hi Annie, thanks for your comment.
      Some breeds of goldfish do turn red with age naturally, it may not be much to worry about.
      However, it could also be some sort of skin irritation or ulceration, test the water to see if there is anything wrong, and observe your goldfishes behaviour, do you notice anything weird, look for signs of illness, discomfort or stress in your fish.
      This article here may help you to identify the problem: costia in goldfish
      If you have any more concerns or would like us to take a better look, you can email us a picture of your goldfish through: speaktous@thegoldfishtank.com
      hope this helps.

      Reply
  5. Hi my orange ranchu who is about three years old has started to turn a bronzey black on its back and tail fin with a black mustache. He is eating properly and is active and my other goldfish are fine. I just did a water test and nitrate was a little high so I have added Prime after doing water change. Is this a natural change?

    Reply

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