Why Is My Molly Fish Turning White? (5 Easy Solutions)

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A few months ago, when I saw that one of my molly fish turned a little white, I thought it was a natural process that didn’t require any attention.

However, a few days later, I saw that the whitening progressed and that some other mollies in the group started losing colors as well. That was when I started investigating.

In this article, you will learn why molly fish tend to lose color, how to solve this issue, and how to prevent it from happening again in the future.

Hopefully, you’ll be able to gain the fish’s colors back, just as I did. So, without further ado, let’s get started.

Why Is My Molly Fish Turning White?

There are a few possible reasons behind a molly fish that is turning white:

1. Stress

Stress is a common reason why your molly fish could be turning white.

Changes in their environment, aggressive tank mates, or being moved frequently can lead to increased stress levels.

Here’s what you should know:

  • Aquarium Change: Molly fish moved to a new tank or environment often experience stress, which can result in their color turning white.
  • Aggressive Tank Mates: If molly fish are housed with more aggressive species, they may become stressed, leading to a loss of color.
  • Frequent Moving: Consistently shifting your molly fish between tanks can cause considerable stress, potentially turning their color white.
  • Overcrowding: Too many fish in a single tank can cause stress to molly fish, leading to color changes.
  • Loud Noises: Unexpected loud noises or vibrations around the tank can stress molly fish, causing a color change to white.

Also Read: Stress In Molly Fish

2. Water Quality Issues

The water conditions in your aquarium directly influence your molly fish’s wellbeing. Subpar water quality can induce skin ailments and color changes.

Pay attention to these elements:

  • Inefficient Filtration: An underperforming filtration setup in your tank might compromise water quality, triggering a whitening effect in molly fish.
  • Temperature Instability: Consistent fluctuations in the water temperature can put molly fish under stress, which might cause their color to fade to white.
  • Elevated Nitrate Levels: Water of low quality, marked by high nitrate content, may result in molly fish changing color.
  • Unsuitable pH Levels: Molly fish favor a pH ranging from 7.5 to 8.5. Water that’s excessively acidic or alkaline might lead to molly fish becoming white.
  • Soft Water: Molly fish flourish in hard water. Exposure to soft or demineralized water can stress them and cause whitening.

Also Read: Do Molly Fish Change Color?

3. Imbalanced Diet

A deficiency of crucial nutrients may induce discoloration in molly fish. If your molly fish isn’t receiving a well-rounded diet, they may start showing white color.

Here’s what you should consider:

  • Monotonous Diet: Offering only a single kind of food can lead to nutrient scarcity, which might cause your molly fish to turn white.
  • Substandard Food: Low-grade fish food might not provide essential nutrients, contributing to color changes in molly fish.
  • Improper Feeding: Overfeeding or underfeeding can stress molly fish, potentially leading to a color shift to white.
  • Absence of Fresh Vegetables: Molly fish need fresh vegetables as part of their diet. Without this, they might encounter nutritional shortfalls and turn white.
  • Protein Deficiency: Insufficient protein intake can cause the whitening of molly fish, as it’s vital for their overall health and vibrant color.

4. Illness

Certain diseases can cause your molly fish to turn white. If your molly fish is sick, color changes can be one of the symptoms.

Consider the following:

  • Fungal Infections: These can cause white patches on the body of the molly fish.
  • Ichthyophthirius (Ich): Also known as “white spot disease,” Ich causes white spots on the body and fins of molly fish.
  • Columnaris: Also known as “cottonmouth,” this bacterial disease can cause a whitening of the skin in molly fish.
  • Skin Flukes: These parasites can cause discoloration, often turning molly fish white.
  • Oodinium: Also known as “velvet disease,” this parasite can cause a dusty, white coating on molly fish.

5. Injury

Physical injuries can result in color changes in your molly fish. If your molly fish has been injured, its scales may turn white as part of the healing process.

Here’s what you should know:

  • Aggressive Tank Mates: Injuries caused by aggressive tank mates can lead to molly fish scales turning white.
  • Sharp Objects in the Tank: If the tank contains sharp objects, molly fish can injure themselves, causing their scales to turn white.
  • Improper Handling: Mishandling molly fish can cause physical injuries, leading to whitening of their scales.
  • Collisions in the Tank: Accidental collisions with tank decorations or other fish can cause injuries leading to whitening in molly fish.
  • Disease Recovery: Post-disease recovery can cause temporary discoloration, causing molly fish to appear white during the healing process.

Also Read: Molly Fish Bullying & Attacking Other Fish

What To Do If Your Molly Fish Turns White

Treating mollies that turn white is related to the underlying cause:

1. Crafting a Stress-free Habitat

Minimizing your molly fish’s stress can encourage the return of their vibrant hues. Here is how you can achieve that:

  • Mitigate Noise and Disturbances: Position your fish tank in a peaceful area with limited foot traffic and noise, which can cut stress in molly fish significantly.
  • Ensure Enough Space: A 20-gallon tank size is a good standard for housing a group of 4-6 molly fish, affording each one approximately 3-5 gallons of their own space.
  • Create Safe Hideouts: Add 1-2 pieces of plants or decor for each molly fish, giving them each their unique spot to retreat.
  • Maintain a Consistent Routine: Feed your molly fish two times a day and adhere to a steady 12/12 hour light/dark cycle to fend off stress.
  • Peaceful Tank Companions: Opt for non-aggressive species famous for their compatibility with molly fish.

On that matter, here are some peaceful species that can be mixed with mollies:

  • Guppies (Poecilia reticulata)
  • Platies (Xiphophorus maculatus)
  • Swordtails (Xiphophorus hellerii)
  • Neon tetras (Paracheirodon innesi)
  • Harlequin rasboras (Trigonostigma heteromorpha)
  • Corydoras catfish (Corydoras spp.)
  • Cherry barbs (Puntius titteya)

On the other hand, here is a list of species that are too aggressive to be mixed with mollies:

  • Red-tailed black sharks (Epalzeorhynchos bicolor)
  • Tiger barbs (Puntigrus tetrazona)
  • Siamese fighting fish (Betta splendens)
  • Green terror cichlids (Andinoacara rivulatus)
  • Jack Dempsey cichlids (Rocio octofasciata)
  • Convict cichlids (Amatitlania nigrofasciata)
  • Red devil cichlids (Amphilophus labiatus)

Also Read: 19 Great Neon Tetra Tank Mates

2. Boosting Water Quality

Keeping ideal water conditions is key for your molly fish’s well-being and color vibrancy. Regularly inspecting and tweaking your aquarium’s water conditions can be beneficial.

Here are some tips:

  • Optimize Filtration: Opt for a filter suitable for a tank size about 20% bigger than your existing aquarium to ensure clear water and minimize toxins. My recommendation: Fluval C4 Power Filter (link to Amazon).
  • Manage Temperature: Maintain the water temperature steady between 72-82°F (22-28°C), using heaters or coolers as needed. My recommendation: Orlushy Submersible Aquarium Heater (link to Amazon).
  • Keep Nitrate Levels in Check: Frequent water replacements (approximately 20-30% each week) can keep nitrate levels under 20 ppm.
  • Monitor Water Hardness: Strive for a water hardness range of 10-25 dGH, adding mineral supplements if the water is excessively soft.
  • Balance pH Levels: Regularly check pH levels to ensure they stay within the 7.5-8.5 range, using pH balancers if required. My recommendation: API PROPER pH 8.2 (link to Amazon).

Also Read: What Is The Best pH Level For Molly Fish?

3. Upgrading the Diet

Improving the diet of your molly fish can enhance their color and overall health. Including varied, nutrient-rich food can make a difference.

Here’s what you should know:

  • Variety in Diet: Alternate between flake food, freeze-dried, and live foods to ensure a balanced diet.
  • High-Quality Food: Use high-quality brands like Tetra or Omega One that often contain color-enhancing nutrients.
  • Proper Feeding: Feed molly fish 2-3 times a day, only as much as they can consume in about 2-3 minutes.
  • Fresh Vegetables: Include blanched spinach, zucchini, or peas in their diet at least once a week.
  • Protein-Rich Diet: Provide protein-rich foods like brine shrimp or bloodworms 1-2 times a week.

Also Read: How To Feed Molly Fish

Brine shrimp are an excellent addition to the mollies’ diet

4. Treating Illness

Addressing health issues promptly can prevent your molly fish from turning white. Identifying the disease and providing appropriate treatment is crucial.

Consider the following:

  • Fungal Infections: Use antifungal treatments like API General Cure (link to Amazon) according to the package instructions.
  • Ich Treatment: Raise the water temperature to 86°F (30°C) for 10 days or use medications like Fritz Mardel (link to Amazon).
  • Columnaris Treatment: Antibiotics like Furan-2 or Kanaplex can be effective against Columnaris.
  • Skin Flukes Treatment: Use anti-parasitic treatments like Praziquantel as per the product’s dosage instructions.
  • Oodinium Treatment: Copper-based medications can be effective, but remember to remove any invertebrates as copper is toxic to them.

Also Read: 15 Molly Fish Diseases & Their Treatments

5. Handling Injuries

Properly addressing physical injuries can help your molly fish recover and regain its color. Providing a safe, healthy environment is essential during this period.

Here’s what you should know:

  • Quarantine Injured Fish: Isolate injured molly fish in a separate tank (10-gallon minimum) to prevent further harm and reduce stress.
  • Treat with Stress Coat: Use a natural healing agent like API Stress Coat (link to Amazon), which promotes recovery and helps heal open wounds.
  • Tank Decor Caution: Remove or smoothen any sharp objects in the tank that could cause further injury.
  • Prevent Collision: Ensure ample space between decorations to allow free swimming and reduce chances of collision.
  • Monitor Recovery: Regularly check the fish’s progress, and consider contacting a vet if no improvement is seen in 5-7 days.


If you are in a rush, here is a quick summary of what I discussed earlier:

  • Molly fish turning white can be caused by stress, poor water quality, imbalanced diet, illness, or physical injuries.
  • Creating a stress-free habitat, optimizing water quality, upgrading the diet, treating illnesses, and handling injuries are crucial to restoring the vibrant colors of molly fish.
  • Maintaining a stable environment, choosing compatible tank mates, and monitoring water conditions are key factors in preserving the color vibrancy of molly fish.
  • Providing a varied and nutrient-rich diet, including high-quality foods and fresh vegetables, promotes the overall health and coloration of molly fish.
  • Promptly addressing health issues and properly handling injuries are essential for preventing and treating color changes in molly fish.