Why is My Goldfish Turning Black? How to Diagnose, Cure, and Prevent Sickness

We all love and care for our pets very much, regardless of if they’re big or small.

While different species require different kinds of care, a goldfish is one pet that’s fairly easy to take care of.

As long as you keep your fishy friend in a properly treated environment and give them healthy food options, your fish’s good health is almost guaranteed.

However, you still need to observe your fish’s behavior and be aware of any changes, especially if your fish starts to turn black.

Here are a few tips on how to diagnose, cure, and further prevent sickness in your friend.

Diagnosing an Issue

As a preface to diagnosing your fish, the best person for this job is your fish’s vet. Consulting with them is the first step, but if you feel confident and qualified for this job, there are a few things you can do.

It’s fairly easy to notice if your goldfish is having problems in their tank. It just requires a little bit of careful attention on your part. A good way to diagnose an issue in your goldfish is to just watch them.

Watch your goldfish for any signs of having difficulty swimming up and down the tank or having difficulty floating easily. These are usually the first tell-tale signs of an underlying problem, such as having a swim bladder issue or problems with digestion.

You may also notice that your goldfish doesn’t eat as much as they used to, or is ignoring its food completely. This could be a sign of overeating, and a blockage in the fish’s digestive tract.

Last but not least, you may see that your goldfish is turning black. You may be tempted to think that maybe your fish has always been a little black, as these changes don’t happen overnight and are usually more subtle.

But in reality, your fish’s skin is indeed changing color. To understand how to cure this color-changing issue, we first need to determine and understand why it happens.

Forever Black?

The truth of the matter is that what you’re thinking is a color-changing issue may not be an issue at all. It’s actually a common occurrence in some species of goldfish to change the color of their skin and scales several times throughout their lives.

Many goldfish turn black because it’s a part of their genetics to be completely black or have some part of their body turn black as they grow older.

In this case, you have nothing to worry about, and your fish likely has a clean bill of health. They are just destined to be forever black.

Turning Black Because of Illness

In the rare case of a fish turning black due to illness, this can be caused by a few different reasons. One of the main things that cause this color change is the environment your fish lives in.

In a tank, goldfish are constantly exposed to the same type of water every day. If there is an excessive amount of ammonia in the water, your fish’s scales can begin to turn black because of the chemical burns they endure due to that ammonia.

Eventually, those chemical burns can alter the color of their whole body, so removing the ammonia in the environment is key to getting the fish back to their regular color.

Another thing that causes goldfish to turn black is the presence of parasites in the water. These color-altering parasites are often found in water snails and can burrow themselves into the skin of unsuspecting goldfish.

This causes the goldfish to change from its shimmering original color to a blackish color. As with the ammonia in the environment, removing the parasites from the water can help to remedy the situation and get your fish back to its normal color.

Curing Your Fish

If your fish has turned black and you’re certain that it’s not due to plain old genetics, there are a few steps you can take to help your fishy friend feel better. The first thing to do is to check the water for excess ammonia.

Having a water filter in place for your fish tank is an easy solution to this, as having leftover food, plant debris, or waste causes the ammonia levels to rise. Keeping a clean tank and sufficiently running filter usually does the trick to lower the ammonia in the water, and get your fish back to good health.

If you believe your fish is turning black because of parasites in the water, you can easily remove those as well. Since these parasites are found in water snails, simply removing any water snails or the like from your tank can be effective.

These snails can come in pretty small sizes, but are mostly found latching on the side of tanks or ponds, so they’re usually easy to spot. Removing them from your fish’s swimming area should help your fish feel better in no time.

If your fish is still not returning to its normal color, it may be time to get the help of a marine veterinarian. Your fish’s vet is specifically trained to handle any and all types of fish sicknesses, so their advice on the situation is a good tool for you to use to figure out how to remedy your fish’s sickness.

Preventing a Sickness

Hopefully, your fish doesn’t have to deal with any sickness, and you find them in good health. In this case, preventative care is the best care for your friend.

You can prevent them from getting sick by doing what you probably already do. Keeping their tank clean is the number one way to keep them healthy, as they spend their whole lives there. Changing out and cleaning their water, decorations, and water filter also helps with this.

You can also give them a good diet to keep their immune system healthy and also keep their digestive system running great. A good variety of flakes, pellets, and even small vegetables, like peas, is a great way to keep your fish happy and healthy.

Finally, having a vet see your fish once in a while is also a good idea. Your fish may not look sick, and they probably aren’t, but having the second opinion of a professional on the matter is great for giving you peace of mind and giving your fish the preventative care they need.

Our pets are our responsibility, and it’s our job as pet owners to keep them feeling their best at all times. A little extra care on our part in observing, diagnosing and curing sickness, and using preventative care goes a long way in giving them the best life they can live.