Why Is My Flowerhorn Turning Black?

The flowerhorn cichlid is a marvelous freshwater aquarium fish. They usually have quite the eye-catching colors, but on occasion, they can turn black.

There can be quite a few explanations for this, and to put your mind at ease, we are going to explain all of them throughout this article. It is our hope that with this information, you’ll be fully equipped to take the appropriate action to help your fish, if any is necessary.

Reasons Why Flowerhorns Turn Black

If you are lucky enough to have a Golden Base Flowerhorn or a close relative of it, the black coloration may actually be nothing to worry about. With these specific flowerhorns, it’s completely normal for their tails, then their bodies, to fade to a completely black color as they age and pass through the juvenile period of their life. If this is the case for you, there is no need to panic. The blackout period doesn’t last forever. Eventually, the black color will begin to fade and a more vibrant color will cover their body.

If you’re sure your flowerhorn isn’t related to the Golden Bases and isn’t simply passing through their juvenile blackout period, the fading of colors usually means one thing – sadly, your fish is stressed.

Fish & Stress

Stress is the last thing you want to inflict your fish with. By causing stress to your fish, a number of things can happen. As you’ve already witnessed, their colors can fade, but their immune system also weakens – making them more susceptible to diseases and death. So what causes stress you ask? Well, here’s a quick list to get you started:

  • Adding new tankmates
  • Incompatible/abusive tankmates
  • Overpopulation
  • Poor water parameters
  • Excessive lighting
  • Lack of hiding spots
  • Lack of space
  • Bright substrate, decor, or background on the tank
  • Fluctuations in water temperature
  • Poor diet
  • Low oxygen levels
  • Incorrect/fluctuations in temperature
  • Excessive noise

The list goes on and on, but I think you get the general idea. If your flowerhorn isn’t comfortable in their home, they are going to become stressed, and being stressed is probably what’s causing your flowerhorn to turn black.

How to Improve Flowerhorn Color by Reducing Stress

Now that we know that it is stress that’s causing your flowerhorn darkening, the obvious next step is to eliminate that stress-causing element in their tank. If you aren’t exactly sure what it is, the best place to start is by asking yourself the following questions:

  • Have I added any new tankmates to the tank recently?
  • Are the tank mates even compatible?
  • Is the aquarium overstocked?
  • Are the decorations providing enough hiding spots throughout the aquarium?
  • Am I providing too much artificial light?
  • Does sunlight beam onto the tank at any point throughout the day?
  • Is the tank’s water temperature correct and stable?
  • Is the aquarium large enough?
  • Does the aquarium have excessively-bright decor, substrate, or background?
  • Is there a chance the oxygen levels are low?
  • Do I need to add an air pump?
  • Have I been doing my regular partial water changes?
  • Have I fed the fish a healthy, balanced diet?
  • Are the water parameters within their acceptable ranges?

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These are by no means the end-all be-all list of questions you should be considering when you are trying to figure out what is causing your fish stress, however they should be a good place to start. Some of the questions may require some research or action on your part. For example, if you have never tested your aquarium’s water parameters before, you will need to learn exactly how to do that and what the acceptable ranges are for your flowerhorn.

If, for whatever reason, you can not seem to determine what is the underlying cause of your flowerhorn’s stress, resort to increasing the frequency of your partial water changes and keep a close eye on your little friend. If you are sure you are providing them with a great home, they could just need a little time to come around.