Why Do Guppies Lose Their Color And Become Pale?

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Guppies are among my favorite types of fish when it comes to fish-keeping. That is because they are both beautiful and hardy. However, quite frequently, I’ve noticed that their tail’s color gradually fades, causing my guppy fish to lose their color. That phenomenon got me a bit worried, so I started researching the topic pretty extensively.

Guppies typically lose their color and become pale due to stressful conditions, including bullying tankmates, low water quality, a new environment, or an underlying fungal disease. However, that could also happen when their nutrition is inappropriate and consists of merely flakes and pellets.

As we move forward in this article, I will teach you how to treat guppies that lost their color and become pale. Guppies that had turned white should catch your attention since they could suffer from a severe disease that could infect the entire tank.

Also Read: Stress In Guppy Fish

Why Is My Guppy Losing Its Color?

It is relatively common for dead fish to lose their color. If your guppy is lying still at the bottom of the tank and the colors have faded, it is probably dead. Check to make sure. You can do this by poking and prodding it, or introducing external stimuli such as food.

However, if your guppy is still active but its colors have started to recede, all the same, the following factors are probably to blame:

1. Stressful Conditions

Stress is one of the most common causes of fading colors in fish like guppies. Primary stress sources include harsh lighting, overcrowding, small tanks, and external elements such as continuous human traffic in the tank’s vicinity. Guppies in tanks that lack foliage are more prone to stress.

Guppies are no different from other fish, and their colors will fade as long as the source of stress isn’t being removed. One of the reasons for that is that stressed guppies don’t eat as much as they should.

2. Bullies

Fighting in the aquarium can cause guppies to lose their colors because the violence induces stress. Guppies shouldn’t be kept with aggressive fish, such as tiger barbs that will chase them around the aquarium and nip at their fins.

You should also keep one male guppy for every 2-3 female guppies.[1] Male guppies are quite aggressive towards one another, especially in tanks with a small female population. They will compete with the females in the expanse of one another.

Also Read: Guppies Staying At The Top

3. Poor Water Quality

Insufficient quality water is one of the most dangerous causes of color loss in fish like guppies. Guppies must be kept in pristine tanks with the right parameters (pH, temperature, alkalinity).[2] Poorly maintained tanks tend to experience a spike in toxins like nitrates, nitrites, and ammonia, which can poison your guppies.

Wild temperature fluctuations are also dangerous. The water should be 72° to 78°F and remain stable. Keep in mind that not only do poor tank conditions induce stress, but they also expose the fish to diseases that can also strip it of its colors in the long run.

4. Underlying Disease

Some diseases have a direct impact on the guppy’s color. One example is ich, which causes white spots to appear all over the guppy’s body.[3] There is also fin rot, which removes the color from the fins. Saprolegnia fungus has been known to discolor the scales, fins, and tail of the guppy.

Other diseases such as dropsy, swim bladder disorder, and gill flukes are not necessarily associated with coloration symptoms. However, a guppy with these ailments will grow pale because of the stress they exert.

5. New Fish

The process of moving fish from their home in a store to an aquarium in your house can induce stress. The same is valid for fish that have to be shipped over long distances. The discoloration is just one symptom among many that a guppy might display when you introduce it to a tank. 

Another symptom is timidity, that is to say, the fish might spend the first few days hiding. If introduced to the tank abruptly, the new guppy is likely to suffer from both bullies and harsh water quality changes. The key here is to make the adjustment gradual.

6. Lack of Food

Guppies should be fed twice a day. It would also be better if you give them meals they can finish in a minute or less. You must avoid overfeeding and underfeeding. You should also maintain a proper diet. 

Please give them various food items, including brine shrimp, bloodworms, flakes, and pellets. Don’t force them to survive on flakes and pellets alone. Guppies need more nutrients than flakes, and pellets can offer. The wrong diet will affect their physical attributes, including their size and color.

7. Artificial Colors

Some store owners inject fish with chemicals to temporarily boost their colors.[4] They do this to compel unsuspecting customers to buy those fish. If your guppy is losing its color, you have to consider the possibility that it is merely returning to its natural, pale, less attractive state. 

Fish in situations of this sort won’t display any other negative symptoms such as lethargy and loss of appetite. That is in contrast to new fish who suffer from bullying and abrupt changes in water conditions.

How to Treat Guppies that Lost their Color?

If your fish isn’t dead, you can always take steps to treat and reverse the discoloration it has suffered, especially if you have successfully identified the cause. The key is to maintain a peaceful, stress-free environment:

1. Ensure High Water Quality

As already mentioned, guppies require a temperature of 76-78 degrees F and a pH of 7.0 or higher.[5] They also prefer hard water that has decent quantities of minerals like magnesium and calcium. The easiest way to keep your fish happy is to maintain the right parameters in the water it inhabits.

It would help if you also eliminated toxins like ammonia, nitrites, nitrates, and phosphates by scheduling and executing regular water changes.[6] Keep the tank clean by changing 15-20% of water weekly. Even if you have a filter, you should consider vacuuming the substrate. 

Remove any dead organic matter you find in the water. That includes plants, animals, and leftovers. Do not let the leftovers to rot since it will quickly elevate the ammonia and lower the pH. That is especially true for relatively small tanks. 

To achieve the desired conditions, I highly recommend getting the API Aquarium Test Kit, which will measure the toxins within minutes.

2. Choose the Right Tankmates

It isn’t enough to keep a male guppy in a tank with an abundance of females. The guppy also requires peaceful neighbors such as platies, mollies, and cory catfish.[7] Keep species like angelfish away from your guppy tank. 

If fish with hostile intentions already populate your tank, use a divider to maintain the peace. You could quickly build it yourself following the YouTube video below. Just make sure the hostile fish and the guppies are separated.

Another option is to put the bullied guppy in a plastic bag. Then, submerge it in the same tank it was so that its tankmates cannot encounter it directly. That will allow the aggressive fish to get accustomed to your guppy, and vice versa.

Also Read: Why Is My Guppy Bullying Other Fish?

3. Avoid Overcrowding

A trio of guppies (two females and one male) requires a tank of at least five gallons. However, the more fish you have, the bigger the tank you require. Don’t force your guppies to survive in a small tank. It would be best to either move them to a bigger tank or reduce the number of fish. 

Even if they survive the discomfort, not to mention the potential oxygen deficiency, overcrowded tanks are difficult to maintain because toxins like ammonia accumulate faster in such environments.

4. Treat Potential Diseases

The treatments you will use to tackle diseases that cause discolorations in guppies will depend on the disease. For instance, Saprolegnia fungus can be fought with antifungal medicine; for that, I highly recommend the API PIMAFIX (link to Amazon). 

You can overcome ich in guppies by cleaning the tank (to remove the parasites responsible for the illness) and using Malachite and Formalin-based products.[8] Vets typically recommend the use of antibiotics for fin rot. In most cases, you are also expected to carry out a water change. 

It is also common practice to gradually raise the temperature (by 2-3 degrees F) and add aquarium salt (one teaspoon of salt for each gallon of water).[9] I also suggest placing the guppy in a separate tank. Maintain a healthy, varied diet. That will strengthen the guppy’s immune system, enhancing its recovery rate.

5. Use the Right Lights

If you have tried and failed to improve your guppy’s color using natural means, you can enhance their appearance by installing the right lighting. Lights in the bright light spectrum (10,000k) will improve the appearance of guppies with shimmery tones. 

Lights in the warm light spectrum (6500-8000k) will encourage your guppy’s orange, red, yellow, brown, and green tones to pop.[10] For that purpose, I highly recommend checking the NICREW ClassicLED Aquarium Light (link to Amazon).

6. Add a Few Plants

Guppies, like other fish, prefer planted tanks. If possible, you can also add decorations. These items can dispel stress by allowing guppies to hide whenever they encounter trouble in the tank. That will also shelter the guppy’s fry.

It would be best if you also considered artificial plants. They don’t require any attention and can serve the same purpose. Either way, make sure that the vegetation’s leaves are broad enough so that the guppies can stay out of sight.


A guppy that has lost its color and become pale is probably going under stress. That happens quite frequently once the fish is introduced to a new tank or when its companions are relatively aggressive. If that is the case, you should place the unpleasant tankmates in a separate tank or use a divider.

However, if your guppy also appears sluggish or its fins seem ripped, you should consider the case of an underlying disease.

In this case, your first step should be moving the fish to a separate tank to avoid spreading. Then, treat the sick guppy in the hospital tank by elevating the temperature. You should also consult a vet for antibiotics or use antifungals.


  1. https://guppyexpert.com/guppies-aggressive-fish/
  2. https://mrfishkeeper.com/color-changing-fish/
  3. https://mrfishkeeper.com/guppy-fish-diseases/
  4. http://www.allabout-aquariumfish.com/2010/09/factors-causing-fish-to-lose-colors.html
  5. https://www.aquariumcoop.com/blogs/aquarium/guppy-care-guide
  6. https://www.petfish.net/effective-advice-on-fish-losing-colour/
  7. https://www.buildyouraquarium.com/guppy-tank-mates/
  8. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2109.2008.02061.x
  9. https://www.thesprucepets.com/using-salt-in-a-freshwater-aquarium-1378797
  10. https://mrfishkeeper.com/best-aquarium-lighting-for-fish-color/