Why Is My Goldfish Turning Black? The reasons And Treatment

You might have asked; ‘why is my goldfish turning black’. This question is very common among those goldfish lovers. For experienced, they know that this is not a good sign. But, they know that there are some ways to cure their goldfish. While this condition is not normal, experienced owners understand several ways to resolve the problem, as well as prevent it to happen again.

Why Is My Goldfish Turning Black? Check Some Important Factors To Consider

Are you trying to take care of goldfish for the first time? Then it is time to prepare the best place and atmosphere for them. Some people don’t know how to take care of goldfish, so they end up in frustration because they find out that taking care of goldfish isn’t as easy as they might have imagined before.

Why Is My Goldfish Turning Black

One of the most common problems that goldfish owners face is the goldfish that turn black. There are several reasons why goldfish can turn black. Among the most common causes why goldfish turn black include:

Water Quality

The first thing to do is to check the surrounding. It can be due to the water quality within the tank. The quality of the water depends on the cleaning frequency. As goldfish excrete often, then owners need to clean the water tank with a high rate of recurrence. While cleaning frequency should be very frequent, goldfish also need bigger tank capacity, because they can produce greater mess than any other kind of fish.

Another excellent solution is to make sure that there is no excessive food left within the water tank. So, feeding goldfish in a small amount is much better so the food leftovers don’t get stuck anywhere within the tank. The decay will ruin the water quality, as well. When owners decide to replace the water, it is also recommended to clean some decorations, particularly in the bottom part of the tank.

Genetic Diseases

Don’t think that goldfish don’t have genetic diseases. Some goldfish suffer from occurring genetics, though this case seldom happens. However, whenever it is caused by genetics, then the changing color isn’t permanent.

Read also: Why My Goldfish Die Prematurely?

Stressful Feelings

Most of the time, the goldfish might have suffered from stress, due to their surroundings. It usually occurs when owners buy goldfish at a carnival. Goldfish can feel stress under such a noisy atmosphere in which they lose their original color. The color will restore gradually whenever they feel that they are comfortable. Goldfish can restore the color whenever they have the strength to recover.  

Stressful goldfish may produce a higher volume of ammonia, in which they also use some unusual behaviors. The main solution for this problem is by adding some decorations while reducing lights for giving a calm atmosphere for this kind of fish.


Parasites are the cause of black-spot diseases that goldfish can suffer. But, this case rarely happens for goldfish that don’t live with other kinds of animals like snails or turtles. Parasites grow whenever there are unknown particles drop into the water. It means the aquarium has a very slight chance to get contaminated with parasites. The parasite larvae can easily enter the goldfish skin. If owners don’t detect this problem right away, then it can be very deadly.

Top Tips To Prevent This Problem

While this problem mostly occurs on most goldfish, there are still some methods to avoid such things to happen. The first and foremost thing to do is to check the water parameter. Though it sounds obvious, many pool owners take this for granted. Having a water parameter kit can help users to check the levels of temperature, pH, nitrates, and many more. Afterward, pool owners can tailor the needs of the goldfish, based on the pool size, water condition, and the number of goldfish within the pool or tank.

The next important step to consider by providing a water filter if goldfish owners don’t plan to add the volume of the aquarium. Upgrading the filter can help clean the water temporarily, though it is still highly recommended to adjust the size of the tank with the number of goldfish within.

Are all those explanations have answered your question: why is my goldfish turning black? Then, you can start taking care of this special fish at your home or office.

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