Why Is My Fish Turning Black? What Do I do?

Finding black spots on your fish can lead to confusion.

Consequently, finding out that your fish is turning black can make you even more confused. Questions like “Is this normal?” “Do I take my fish to a doctor?” or “Is my fish going to die?” will pop up in your head.

My initial advice would be to calm down as your fish turning black is not as big of a problem as you are making it out to be. People who have fish have reported this issue several times.

It usually occurs when your fish is in stress, or it has some sort of illness, which is not fatal.

No need to worry, you can take several steps to ensure that this doesn’t happen to your fish. And, even if it does, then you’d know how to deal with it on your own.

Why Are There Black Spots On Fish? (Video)

Black Spots On Fish

You have to identify whether your fish is turning black, as in changing its color or are black spots appearing all over it.

To begin with, if you see black spots on your fish and they are increasing with each passing day chances are that your fish has contracted the “Black Spot Disease”.

According to this website, black spot disease is fairly easy to control and treat as compared to other diseases in fish.

In brief, your fish will exhibit the following symptoms if it has the disease:

  • Irritated Skin: Your fish will show signs of irritated skin by scratching its head or its body against a hard object because its body is itching all over.
  • Small Spots: This is really the first symptom of black spot disease. Tiny black bumps or black spots in the form of a birthmark can appear on the fish’s body even though it was not there before.
  • Difficulty in Breathing:  Seeing your fish coming to the surface and gasping for air is a dead giveaway that something is wrong. This, with all the symptoms mentioned above, confirms the presence of Black Spot Disease.

How To Prevent Black Spot Disease

Hence, now you know that your fish does have Black Spot Disease so what do you do about it? How do you prevent it?

According to Wikipedia, this disease is caused by a flatworm which is a parasite and forms as a cyst at a fish’s skin. It is very easy to cure.

Regularly, precautionary steps are taken to ensure the safety of your fish which are mentioned below:

  • Keeping the water tank clean
  • Regular use of aquarium salt
  • Fresh food should be given to fish

Although these are basic steps, a little goes a long way. There are steps you can take after your fish has this disease.

Such as:

  • Salt Bath: As the title suggests, place your fish in aquarium water that has roughly 2-3 tablespoons of salt. This method is found to be very effective in treating fish-related diseases.
  • Freshwater Bath: This bath can help your fish to calm itself and treat its anxiety by a thorough quarantine process.

Furthermore, to avoid reinfection in the future, try to not use the previous water tank and find an alternative tank to keep your fish in.

Fish Has Very Black Eyes

Many fish are known for changing their eye color. Similarly, if you notice your fish changing its eye color, it’s nothing to be afraid about.

Your fish can darken their eyes almost deep pitch black due to many reasons.

According to many studies and experimentation, it was found that fish usually darken their eyes when they are under stress.

Besides this, there are other things that can make a fish’s eyes pitch black.

Some are mentioned below:

  • Aggression: According to a study, Trinidadian guppies are known for changing their eye color to pitch black when they are angry or going to be aggressive. It’s a type of signal from this species of fish to let the other fish know that they need to back off.
  • Traumatic Event: Traumatic incidents such as getting out of the water, which leads to difficulty in breathing, can also cause fish to darken their eyes. Nevertheless, a major sign of stress.
  • Ammonia Levels: Ammonia levels in a new fish tank are a threat to the safety of your fish. The new environment and ammonia poisoning cause your fish to stress out even more.

What Causes Fish to Turn Black?

Dark and Black Spots in one thing, but what happens when your fish is actually changing its color to black? And it doesn’t even have the Black Spot Disease?

Generally speaking, it is not normal for a fish to turn black under any circumstances. Contacting your vet is the only option or step that should be taken by you.

The reason why I say this is because fish turning black is not a common occurrence.

On the other hand, if you have a goldfish, then the narrative changes completely. A number of people who own goldfish have reported this issue.

So, why does this happen?

Many factors count. Such as:

  • Ammonia: High levels of ammonia in a fish tank can be very harming. Monitor the pH levels regularly in order to maintain the good health of your goldfish.
  • Environment: Stress due to moving to a new place and a new tank is never good for a fish, especially a goldfish. Make sure it is comfortable.
  • Genetics: Goldfish can change color over a period of one to two years, and this color can also be black. Shortly, no need to worry or panic.
  • Food: Color enhancers in processed food are not exactly helping out your goldfish in this matter. They also play a huge role in changing your goldfish’s color to black.
  • Poor Hygiene: Can’t remember the last time you cleaned the tank? There you have it, the reason why your goldfish is having this change.

To summarize, be responsible and consult a vet if you think your goldfish is sick.

Steps You Can Take To Prevent Illness in Your Fish

“Prevention is better than cure” and rightly so. Preventing something that could happen in the first place is a better measure than to visit the doctor.

Shortly, here is what you can do to make sure that you don’t have to visit the vet after your fish gets sick.

  • A good, healthy water tank has the right temperature, pH levels, and low nitrate levels
  • A proper meal that is fed twice a day in a minimal amount to overcome overfeeding is what your fish needs
  • Separate tank for wild fish as they have diseases and without quarantine, they can pass on those diseases
  • Get a good quality water filter
  • Too many fish in a single tank can also cause problems such as conflict among fish

You can also find your fish not being able to eat. Loss of appetite, fading of color, or long periods of inactivity usually mean that something is wrong with your fish.

It may have gotten a bacterial or fungal infection, which can also be avoided if proper care is taken, but then again, mishaps can happen anytime, and there is no one to blame at the end.

Furthermore, keeping too many fish in a single tank can lead them to bully each other in order to exert power.

That is why it is said to keep them apart and do a little research on the type or species of fish you are getting, to avoid any trouble later.

When To Consult A Doctor

I have mentioned several times that consulting a vet is the right thing to do if you are not satisfied. But, when is the right time to consult a vet?

How do you recognize the fact that your fish need medical attention? Your fish started behaving a little weird, and you don’t know when are things going to go back to normal?

When severe symptoms surface that is when you should contact the vet.

Severe symptoms include:

  • Blood pouring from your fish’s mouth or gills
  • The white fur-like substance is present on your fish’s gills
  • It develops a fungal or bacterial infection
  • Not being able to swim (at all) and severe laziness or inactive
  • Turning upside down in the tank
  • Loss of appetite

Fish vets are very rare. Before coming home with a tank full of fish, do some searches and see whether a fish vet is available near your house.

Note down their address and number in case of emergency if it’s the first time you are having fish as a pet.

Other Related Questions

How often should I change the water in the aquarium/the fish tank?

It depends on the size of the tank. A small tank should be cleaned at least once every week and a large tank requires two changes in a week.

Can a fish die from stress? Is stress really that bad for a fish?

Death of a fish from stress is not common but not unheard of. Stress can be really bad for your fish and different stress levels affect your fish differently.

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