White Specks In Fish Tanks: All Reasons & Solutions

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Many aquarists wake up one day to find their tank covered in white spots. The first time this happened to me, I had no idea what it was or if it would harm my fish.

As I delved into this topic, I learned that there are actually many reasons behind it. This led me to write this article.

Let’s dive right into it.

What Are The White Specks In My Fish Tank?

If you find white spots in your fish tank, these are usually the culprits:

  • Daphnia
  • Limpets
  • Hydra
  • Snail eggs
  • Mussels

As we go along, I will expand on each of them, and share some useful tips on how to get rid of the white spots.

1. Daphnia

Magnified image of daphnia under a microscope

Daphnia cause trepidation because professional aquarists call them water fleas. But unlike the fleas on your dog, daphnia are relatively harmless.

  • What Are Daphnia?

Daphnia are tiny crustaceans roughly 0.2 to 0.4 inches in size. They can take on a white, green, yellow, or pink color.

They multiply rapidly because the crustaceans transition from conception to adulthood within a week.[1] But they are not a threat. 

Admittedly, Barbara D Petty, Ruth Francis-Floyd, and Roy P. E. Yanong (College of Veterinary Medicine, University of Florida) identified daphnia as intermediate hosts for Cammallanus spp.[2]

Camallanus is an intestinal parasite.[3] But before you panic, you should know that cases of daphnia harming fish in home aquariums are rare. 

These creatures are actually a beneficial addition to your tank. 

A paper in the Global Scientific Journals (Padjadjaran University) noted that daphnia are an appealing natural feed for guppies because daphnia are slow-moving and easy to catch.[4]

But some aquarists hate the impact of daphnia on their tank’s appearance. They don’t want to see white specks floating in the water or on the aquarium glass.

  • Why Does My Fish Tank Have Daphnia?

Surprisingly, nothing causes daphnia. These crustaceans typically enter an aquarium when you buy and add them to the water. 

Many aquarists rear daphnia intentionally to feed the crustaceans to their fish. 

If you’ve never purchased or cultured daphnia, they most likely hitched a ride on new fish and plants. 

  • Where Are Daphnia Usually Found?

They float harmlessly in the upper sections of the water. Look for them on the water’s surface.

Quynh Ann Vu Le from Chonbuk National University had daphnia Magna eggs that turned white without hatching. In other words, some of the white specks in your tank could be eggs.[5]

  • How Can I Tell If The White Specks Are Daphnia?

Daphnia are too small for you to identify their physical features. They look like white specks that move around in the water. 

You can collect a sample of daphnia with an eyedropper before taking a closer look under a microscope.

  • How Do I Remove Daphnia?
  1. Avoid adding new fish and plants to your tank, at least for a while. You may also consider changing your retailer.
  2. Stop feeding your fish for a few days. That will encourage them to eat the daphnia.
  3. Perform routine water changes (15 to 20 percent each week).
  4. Clean the filter, as this part usually contains large colonies of daphnia. However, avoid cleaning the filter media, as it contains beneficial bacteria.

2. Limpets

Limpets are harmless creatures. People tolerate them because limpets eat algae, fish waste, and dead plants.

  • What Are Limpets?

These creatures are often compared to clams, snails, and slugs because of their appearance. 

If their impact on your tank’s appearance doesn’t bother you, you can afford to ignore them. Limpets don’t eat live plants, and they are not a threat to fish.

  • What Causes Limpets?

They will hitch a ride on new additions to the tank, including plants, rocks, and decorations from contaminated aquariums.

  • Where Are Limpets Usually Found?

As scavengers, they spend their days crawling over any surface in the aquarium in search of food. You find them on glass, substrate, plants, decorations, filters, etc.

  • How Do I Identify Limpets?

Limpets look like white or golden flakes and specks in the water, which is why some aquarists hate them. 

Some may confuse them with snails, especially when you see their muscular foot. But the conical shell attracts comparisons to clams. They can grow to 2.3 inches. 

  • How Do I Remove Them?
  1. Perform regular water changes (15-20% every week).
  2. Remove any seen waste (leftovers, algae, dead organisms, etc.).
  3. Vacuum the substrate at least once a week.
  4. Add scavengers and algae eaters. They will eliminate the limpet’s food source. 

3. Hydra

Hydras appear in both freshwater and saltwater environments. Therefore, you cannot avoid them. 

These creatures can easily go unnoticed because of their small size (0.4 inches). But they become impossible to ignore once they multiply.

  • What Are Hydras?

Hydras are polyps with tubular bodies, sticky feet, and tentacles. 

They don’t have brains, musculature, circulatory or respiratory systems. You will find them in green, white, and light brown colors.

  • How Do Hydras Get To Fish Tanks?

They enter your tank via new plants and decorations. Some hydras will lie dormant in your aquarium for months after their introduction before suddenly blooming.

As such, it may not occur to you to connect their presence to the plants and decorations you added a few months ago.

  • Where Are They Usually Found?

Hydras will cling to rocks, filters, plants, wood, and any other reliable surface they can find in the aquarium.

  • How Can I Identify Hydras?

You may not notice the physical attributes of these organisms because of their tiny size. But if you touch the creatures, they curl into a ball because they feel threatened.

  • How Do I Remove Them From My Aquarium?
  1. Wipe them off the tank walls with a sponge.
  2. Add mollies, gouramis, guppies, or any other fish that eat hydras. 
  3. Remove and soak artificial plants and decorations in a bleach solution if they are infested with hydra.
  4. Use commercial chemical products that specifically target hydras, like the SOBAKEN Genchem Hydra Killer (link to Amazon). As a full disclosure – I have never tried this product myself.

4. Snail Eggs

Aquarium snails lay eggs. Those eggs are not dangerous unless they die and rot, producing ammonia.

Snails begin their lifecycle as eggs. They are usually transparent with slight coloration that becomes more prominent as the eggs develop. 

Eggs usually originate from snails. Some snails can reproduce alone. Others require a mate.

You also have eggs that enter tanks by hitching a ride on new plants, decorations, fish, and other additions.

  • Where Are Snail Eggs Usually Found?

Snails will lay eggs on any safe and stable surface they can find, including plants, rocks, driftwood, ornaments, etc.

  • How Do I Know If The White Specks Are Snail Eggs?

Snails usually lay eggs in jelly-like clusters. While those eggs are white or translucent at the start, they will develop dark spots over time.

Eggs that don’t change color are not fertilized. They will eventually rot.

  • What Should I Do With Those Eggs?
  1. Let the eggs hatch and grow the snails. Remember that snails reproduce quickly, so you risk an outbreak with this option.
  2. Let the eggs hatch and remove the snails.
  3. Let the fish eat the snails. Any fish that can fit these tiny eggs in its mouth will happily feed on them.
  4. Remove the eggs manually. Here is an article where I explained how to do that properly.
Magnified image of fertilized snail eggs under a microscope

5. Mussels

Mussels are a poor addition to most tanks because they don’t do anything. They just sit there. The creatures can also carry parasites.

  • What Are Mussels?

Mussels are comparable to clams. You wouldn’t be wrong in calling them bivalve mollusks. 

They reproduce when male mussels release sperm in the water. Their female counterparts suck this sperm in using siphons.[6]

This matters because that white substance you see in the water could be packets of glochidia.[7]

According to experts in Holt, Florida, glochidia are parasitic larvae that attach to the gills of host fish. 

The larvae won’t harm the fish. It wouldn’t serve their purpose. It takes a few weeks for the larvae to become young mussels. 

  • What Causes Mussels?

People usually buy mussels and deliberately add them to the aquarium. 

According to one paper in Ecology and Evolution (Alexandra Zieritz, Juergen Geist, Bernhard Gum, Kuehn), some freshwater mussels are endangered.[8]

Therefore, no one would blame you for rearing these creatures in an effort to conserve their kind. The larvae can enter your aquarium by hitching a ride on fish. 

  • Where Are Mussles Usually Found?

You find them partially submerged in the substrate.

  • How To Identify Mussels?

Unlike clams, mussels have a wedge shape, thin, smooth shells, and longer bodies.

  • Should I Remove Mussels?

You don’t have to remove them. Mussels will filter your water. 

But if you hate the look of their white larval offspring, you can manually remove the creatures. If the white specks persist, perform a water change.

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White spots in fish tanks have various reasons, including daphnia, limpets, hydra, snail’s eggs, and even mussels. Fortunately, it’s pretty easy to overcome.

In most cases, regular water changes and tank cleaning will help the issue gradually resolve itself. Vacuuming the substrate is a crucial step in most cases.

Snail eggs are a little different in this regard. If you want to get rid of them, you’ll probably have to remove them manually. Just remember to wear gloves.


  1. https://be.chewy.com/fish-food-daphnia/
  2. https://www.msdvetmanual.com/exotic-and-laboratory-animals/aquarium-fish/parasitic-diseases-of-fish
  3. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/camallanus
  4. https://www.globalscientificjournal.com/researchpaper/THE_EFFECT_OF_Daphnia_sp_ON_THE_WATER_QUALITY_MAINTENANCE_MEDIA_AND_GUPPY_FISH_Poecilia_reticulata_ACTIVITY_IN_FRESHWATER_FISH_SEED_CENTER_CIMAHI_CITY.pdf
  5. https://www.researchgate.net/post/Why_Daphnia_magnas_eggs_stay_long_time_in_brood_chamber_and_turn_into_white_color_until_death_without_hatching
  6. https://molluskconservation.org/MUSSELS/Reproduction.html
  7. https://myfwc.com/research/freshwater/species-assessments/mollusks/host-fish/
  8. https://onlinelibrary.wiley.com/doi/10.1002/ece3.220