Why Are My Neon Tetras Losing Their Color? {Are They Sick?}

Neon tetras losing their color is concerning. Why are my neon tetras losing their color?

Are they getting sick or is this normal?

In this article, we’ll try to bring some color back to your neon tetras and try to figure out what’s going on.

Why Are My Neon Tetras Losing Their Color?

It’s normal for neon tetras to lose some color at night or in the dark.

A stressed neon tetra will also lose color, but with a little work, we can help restore the vibrancy back in their color.

We’re glad to help you with this colorful topic. You should not be too alarmed just yet. Let’s go through this step by step.

Are My Neon Tetras Losing Color Because They Are Cold?

The best temperature for neon tetras in your aquarium should be around:

  • 72°-76°F or 22.2°-24.4°C.

Maintaining this temperature and keeping it constant will require water heater.

Neon tetras are tropical freshwater fish. They prefer warmer waters and their colors will show it. If the seasons change and your room becomes colder, the heater in the tank will become even more necessary.

Are My Tank Lights Causing Neon Tetras To Lose Their Color?

Bright lights will interfere with the circadian rhythm of neon tetras.

  • Neon tetras don’t require more than 14 hours of light.
  • Turning off the lights at night is important for their color to stay vibrant.

The neon tetras have chromatophores that pull in light rays. They are cells that produce the bright pigments in neon tetras that we know and enjoy. Too much light will overdo it and cause their color to fade.

It’s a good idea to get a timer for your tank lights to turn off automatically after 12-14 hours. This will help to ensure that your neon tetras don’t get stressed by too much light and lose color.

My Neon Tetras Have Lost Their Color in The Dark. Is This Normal?

Yes, it’s quite normal for your neon tetras to lose some of their color at night. The color can seem dull or faded, but it should be back to normal in the morning.

The loss of color from too much light is gradual and longer lasting. It causes stress and could lead to sickness. The faded color of neon tetras at night is temporary and can restore itself rather quickly in the morning.

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Are My Neon Tetras Losing Their Color Because They Are Stressed?

You can see the most obvious signs of stress by noticing the faded color of your neon tetras. Look closer to see if there are any other signs. Here are a few in no particular order.

  • Strange swimming patterns: Frantic, bumping or swimming at the bottom of the tank with locked fins isn’t normal. This indicates stress.
  • The tank is too small: The size of the tank is important for your neon tetras to feel comfortable.
  • Aggressive tankmates bullying them: Bullying will cause your neon tetras major stress.
  • Nitrates And Ammonia above 0ppm: Make sure these values remain at 0. Neon tetras will get stressed if the water parameters are not right.
  • Keep the temperature between 72°-76°F: If it’s too cold for these tropical fish, this will stress them out.
  • The loss of color lasts all day: If their color doesn’t return to normal through the day, then the stress is causing this physical problem.
  • Swimming alone: If your neon tetra is swimming alone, then they are stressed. They need company. Add more neon tetras.
  • Neon Tetra Disease: Unfortunately color fading is a sign if this terminal illness. Quarantine your neon tetra and see if they improve with a healthy feeding schedule.

Are My Neon Tetras Losing Color Because of Poor Cycling?

Cycling plays a crucial role in maintaining a healthy habitat for your neon tetras. A tank could become toxic and this could lead to their loss of color.

Make sure to test the water weekly. Use a water testing kit to ensure the correct water parameters. A sign of ammonia poisoning in neon tetras is the loss of color. Excess nitrate is also a major problem. Both values must remain at 0.

Once your tank has been cycled successfully, you’ll notice that your neon tetras will return to their playful behavior. This will also help to restore their color.

Are My Neon Tetras Sick?

A pale neon tetra may actually be sick. If they are acting weak and sluggish on top of the faded color, then a disease might be imminent or already taking over.

It’s a good idea to quarantine your neon tetra. There are medicines available, but Neon Tetra Disease is not curable. Add more vitamins to their food by dipping their meals in these solutions or drop them directly into the tank.

Make sure to consult professionals and read instructions on the side of bottles carefully before deciding to treat your neon tetras.


Neon tetras lose color at night when they’re resting. This is normal. The loss of color is a problem when coupled with other signs indicating stress or illness. Make sure the tank isn’t too bright for too long and their color may get restored.

Keep observing carefully for other indicators of stress mentioned in this article and remain patient. When we try our best and hope for the best, usually our neon tetras will respond positively.

We hope your neon tetras will be vibrant, bright and playful again very soon.


Thank you for stopping by at HelpUsFish.com. We have plenty of articles on a wide variety of aquatic and marine life that may also pique your interest. See you again soon!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.