Goldfish are used to be petted more often than cats and dogs. So, a lot of questions about them. People often ask the question why is my goldfish turning black. Is then a reason to worry? We are going to explore the reasons to answer your question. So, get into it. 

How goldfish get colors and how it turning into another 

In the skin of fish pigmented cells are called chromatophores and melanocytes. The melanocytes give them that black dark pigmentation and the chromatophores give all the other colors. In the process of maturing, the fish can turn from bronze towards orange and white and he can also get fish stopping in the color-changing process into intermediate phases where they may stay there pretty much for the rest of their life. 

This color-changing happens very often while the fish are young and maturing but it can happen pretty much at any stage of their life. With the normal changing of the color distribution, you can see where the darker pigmentation would move towards. Extremities of the fish over here you can see the orange with the black the dark portions are the tips of the fins and on the dorsum and sometimes you might get like a little mustache forming on the front of the fish where the mouth is. 

Why is it turning black? 

You can also see here with the fish that is turning white the orange then the darker color which is the orange is moving towards the extremities. You can see the distribution of the black pigmentation is different. It is quite patchy.  


There are quite a few reasons why this could be and most often. It is due to some irritant or damage to the skin. Now we have done some microscopy work on this fish that is to rule out the possibility of any sort of external parasites like skin flute strip Idina white spot disease and things like that and we found nothing significant on the slides. 

Take a much closer look at this fish you can see that the areas where it is got this dark coloration the skin or the flesh that is looking lumpy and that tells me it is more likely due to trauma. If we have a look at the fish from the top a bird’s-eye view, if we have a look at the distribution of the dark lesions on this fish it is symmetrical and it is linear.  

Should I concern about this? 

It is mostly happening because of a disease or bad water condition. So, you must worry about those factors, not the color changing. You need to act if you want your goldfish alive because Black color changes could be a sign that your fish is suffering internally.  

Ammonia in the tank 

Many times, ammonia is the cause for goldfish turning black. It starts with their fins and next to the body. One of the most important things aquariums do is maintain Ammonia lowest level possible, ideally 0 ppm. The main reason to increase ammonia in the tank is the fish itself. Their excretory system releases a considerable amount of ammonia. The decaying plant can also increase ammonia levels. 

You should have known how ammonia turns goldfish skin black. Well, you cannot see if ammonia in water and what it does to fish either. Ammonia burns goldfish skin. So why black? Well, black is the sign of fish heal from those burns. That is right if goldfish skin turned black that often means the ammonia level has backed too normal. But do not assume anything. Check the water. If anything above 0 ppm, Clean the water. 

Maintain ammonia at 0 levels is not hard as you think. Clean the tank on a proper schedule that is enough. Filtering and recycling water will help. If you do not care about cleaning your tank it will be bad for your goldfish. 

Genetic background 

Changing skin color at some stage of their life is common among mixed-breed goldfish. They do not usually turn to black. But it is possible and happened. Mix breed goldfish are the cheapest goldfish variety in the market. Maybe changing colors is one reason for their price s are low. However, there is a probability to pureblred goldfish turn black. Extremely rare but can happen. Goldfish turning black because of their genetics is nothing to worry about. It does not kill the fish or shorten its life span. 

Can black goldfish turn back to their previous color? 

If your goldfish turn back because of its genetics so there is no way, it returns to the previous color. It will spend its life span without problem because it’s just the skin turns black. But if your goldfish burnt by ammonia, you must worry about if the fish make it or not. Ammonia burning can kill fishes. But if goldfish make it black will fade away slowly. Also, keep in mind turn black is a sign of healing. So, avoid ammonia increasing from here. 

So, after excluding external parasites and water quality issues we can determine that these lesions are due to trauma or slightly due to a bird or a cat attack.  

With the color of goldfish, some can be pale, and some can be very intense, and people often ask is there any way to enhance the colors on my goldfish. One of the ways to enhance the color of your goldfish is to have them in outdoor ponds exposed to natural sunlight. You can also enhance the color of your fish by feeding them foods that contain astaxanthin or carotenoids as the Xanthian. It sounds familiar because it is what they use in the feed of poultry to give you that orange color in the egg yolk or the orange color in salmon flesh.  

So that’s about goldfish. Keep eye on your lovely pets. So you can find if something is going wrong and avoid it. There are more things you should know. Stay with us for more pet facts.  we have plenty of articles for you. Stay with us. Read more