White Spots on Fish Tank Glass

Small White Spots On Fish Tank Glass: Causes and Solution

White Spots on Fish Tank Glass

You might be surprised to find little white spots on your aquarium glass, woody objects inside and even on the decorations inside a fish tank. Some of these spots can be detected early on, but the numbers could end up increasing with time if you don’t act fast.

Whilst there is nothing to stress about in some cases, it is important to understand what the white spots actually are so that you can act accordingly. The spots are not permanent and can easily be eliminated with some simple methods.

This blog will provide you with a thorough inspection of your fish tank’s white spots with simple solutions to eliminate them completely.

What are those white spots on my fish tank glass?

There can be a number of reasons behind the appearance of the spots and tend to make the fish tank look unattractive and dirty. In worst cases, they may end up causing harm to the aquatic species roaming inside the tank.

The truth is that there are many more organisms that exist within the tent other than the ones that you have purchased. It may even take weeks or months before you notice these additional occupants.

Fishes and plants naturally attract other living beings like plankton, algae, limpets, daphnia, hydra or a myriad of other aquatic species.

The white dots that are troubling you are very likely to be these small living creatures hanging on the glass or even their eggs.

Let’s go through some of the characteristics that will help you to better identify these creatures.

1) Hard white spots in aquarium – Limpets

Rigid white dots can be formed on the fish tank glass by the presence of tiny snail eggs or limpets. They are not likely to move and instead build hard white spots on tank glass.

They are harmless to the living fishes in the aquarium. Although, if they do build up, it will make your aquarium look much less attractive from the outside.

2) Soft white spots in groups – Nerite Snail eggs

These smooth and sloppy white dots are produced by the eggs of the parasitic Nerite snail. Nerite Snail eggs look like little white ovals resembling sesame seeds and are most easy to notice on dark surfaces, the fish tank glass or on decorations and ornaments. 

The white bumps you see are not actually the eggs of the Nerite Snails themselves, but are instead small capsules that could contain anywhere between 30 to 100 eggs!

These can rapidly multiply and invade the aquarium if you do not take action right away. Additionally, the waste that is produced by these pests can affect the water quality which may disturb the fish.

3) Moving white spots – Daphnia

There are lots of tiny creatures which appear as little dots in a glass. These spots are characterized by certain motions and perhaps caused by daphnia or small helminths like worms.

Their presence might sound unpleasant but in reality, they are an essential part of the fish tank ecosystem. So, unless they are bothering you from a visual standpoint, you don’t have to worry about these small organisms.

4) Hydra infestation

Sea Anemones and Hydra are related, and both species catch food in very similar ways. They often live in tiny colonies and divide for their reproduction.

When catching prey, hydras employ what seem to be tiny hairs arranged in a star pattern; their colors range from white to green.

These tiny hairs may pierce a fish’s scales if they are small enough and actually contain a numbing poison. A Hydra infestation is harmful and you should look to quickly eradicate them from your fish  tank before they become a problem.

How To Get Rid of White Spots on Fish Tank Glass?

If you investigate the spots with a magnifying glass, you will surely be able to determine the culprit that is causing them helping you to use the right method to get rid of them.

How to get rid of hard white limpet spots

The rigid white spots can be removed by scrubbing them with a sponge. This may take a bit of effort but you will get a flawless shine to your glass when you are finished.

How to get rid of soft white Nerite Snail spots

These smaller soft cohorts of spots can similarly be wiped out by scrubbing, but the only difference is that you might need to clean the tank frequently since these snail eggs are produced rapidly. 

How to get rid of moving white Daphne spots

As previously mentioned, these aquatic organisms are essential to the fish tank ecosystem and actually benefit the fishes living in your tank. So for this reason, we actually advise you not to do anything and instead leave them to co-exist with your aquatic friends.

How to get rid a hydra infestation

We won’t lie to you, it can be very frustrating to get rid of a hydra infestation. Luckily, we can say there are a few effective approaches you can take. You can introduce a blue (or three-spot) gourami which enjoy feasting on these small creatures. 

If that is not possible, you can instead choose to take out every fish and subsequently increase the temperature to around 105 degrees Celsius, adding a mixture of 4 teaspoons of salt per gallon of water. It must be noted that this process could be harmful to the plants in the tank so be sure that this is the right decision for you before attempting it.

How To Remove Lime Stains from The Aquarium Glass Safely?

Sometimes spots may simply be lime stains which can make your fish tank look a little dirty.

You might feel a strong desire to utilize household cleaning supplies like detergents or bleach on these spots to get rid of them.

We completely advise against this however, as even the tiniest trace of these products can be toxic to the fish and can result in killing them off.

There are special products that are designed for the safe removal of lime build-up from aquarium glasses. We specifically recommend using this product which tackles these stains quickly and efficiently whilst keeping your fish nice and safe:

Buy Fritz Aquatics Fritz Aquarium Glass Cleaner Now

If you’re looking for a DIY solution with products that you have laying around your home. You can try applying vinegar after drying the tank. Vinegar is an inexpensive natural acidic agent that dissolves the lime without harming the life inside the aquarium.

A simplified process to clean up this stubborn limescale is provided below:

  1. Transfer the fish from your aquarium to a holding tank.
  2. Once the fish are completely relocated, remove all the water from the tank.
  3. Remove the plants and decorating structures as well
  4. Dry the tank or soak the water up using a towel.
  5. Apply a sufficient volume of the vinegar upon the affected glass surface.
  6. Leave it for 15-20 minutes.
  7. Now scrub the glass surface with soft materials like cloth
  8. As cleaning is done by now, rinse the tank with water before depositing water again.

Perform all the steps carefully to avoid damaging the glass or the glue holding the glasses together.

Clean-The-Aquarium-Glass-

How Do I Prevent the Formation of This Lime?

Check the water supply line to your fish tank routinely since evaporation is the major reason behind mineral accumulation.

Warmer days will enhance the evaporation rate and low humidity in winter will increase evaporation as well.

As water evaporates, the mineral concentration in tank water gets increased towards a higher lime density. In such a case, you should try using distilled water since all the mineral contents are removed in distilled water.

But this may be a bit costly and not applicable for fishes that require additional minerals in the feed.

You can check the water quality routinely. Inspection of the pH, alkalinity and hardness of the water will give you a view of when to change the water and reduce the chances of possible lime accumulation on the glass.

This will also help keep a sound water environment for the healthy living of the fish.

Keep your fish tank looking clean and fresh

Excellent water quality is necessary for the fish living in a tank. Hence, the fish tank should frequently be a subject of inspection regardless of identifying any spots. A water filter can help to improve the overall quality of the water in your fish tank as well as removing any other unwanted elements in your tank such as the white stringy stuff you may sometimes see appear in your tank.

Cautious measures should be taken when dealing with the spots, since the glass materials can often cause accidents. Look out for steep edges when cleaning the tank.

On the other hand, some small crustacean species appearing like spots on the glass are actually beneficial for your fish. If you ever forget or cease to feed your fish, they will survive a few days consuming these little organisms.

FAQs about white spots on fish tank glass

What are the white bubbles on my aquarium glass?


White bubbles may start to form on your aquarium glass when the liquid inside becomes agitated. They are harmless and simply water pockets filled with oxygen. They may appear when you are filling up or topping off an aquarium or even from your air pump.

What are the white eggs on my fish tank glass?


These white eggs on your fish tank glass could be fish eggs and are especially likely if you have observed specific breeding behaviours among your fish such as the cleaning of surfaces or even guarding certain areas in your tank. Fish species such as Angelfish and Discus will tend to lay eggs on the fish tank glass if nothing else is available.

Other possibilities may include fungal growth or algae that may resemble egg spots. It is important to confirm if they are fish eggs by closely observing your fish’s behaviour or seek advice from an aquarium expert if you are unsure about classifying them.