How to Remove Protein from Freshwater Aquarium?

The term “surface scum” refers to a coating that forms on the surface of the tank that is white, greasy, or milky in appearance.

You may see a protein film behind this thin layer of white sludge. As it accumulates, it hinders the tank’s ability to exchange gases and reduces the amount of oxygen available to the fish.

Keeping scum at bay from your aquarium is as easy as using a few of these tried and tested ways.

First, manually skim the oily surface of your tank. The second option is to use an internal or external surface skimmer. Last but not least, reduce the amount of scum in your tank.

This article will explain the dangers of protein build-up, the steps to remove it, and how to maximize the potential of a protein skimmer.

How Do I Get Rid of Protein Film in My Fish Tank?

The cleanliness of your aquarium and the well-being of your fish both depend on how well you maintain your tank.

The quickest and easiest technique to get rid of the oil coating is by first turning off your aquarium’s equipment and letting the water settle for a few hours.

A protein film will float to the surface, where it may be easily wiped away or filtered out with a paper towel or aquarium net. It might take several tries before it’s completely gone.

A measuring cup can be utilized in the process of removing oil films of a more substantial size.

As you pour the water into the cup, you should take care not to disturb the protein coating that is on the surface of the tank, and you should attempt to just immerse the rim.

Continue doing this until there is no longer any accumulation of protein.

If you continue to struggle with oil slicks, consider buying a surface skimmer.

Surface skimmers remove hydrophobic surface films and scum to promote aquarium gas exchange and oxygenation, unlike protein skimmers that remove dissolved organic molecules (DOM). More importantly, it’s cheap!

What Causes Too Much Protein in Aquariums?

The scum that forms on surfaces is often a microbiological biofilm. In other words, a vigorous and slimy cluster of bacteria and other types of microorganisms. There is a multitude of factors that contribute to the buildup of protein in the aquarium.

Excess Organic Waste

In new tanks or tanks with undersized filters, the filter does not digest organic waste rapidly enough and accumulates at the surface, where good oxygen levels sustain a healthy microbial colony that feeds on it.

Furthermore, there are several kinds of fish food, and many of them include fat in them. Fish meal dissolves in water, and any fatty or protein-rich remnants rise to the top.

Variation in Plant Growth Parameters

New equipment, light, or fertilizer can cause this.

Plants produce proteins that form an oily layer at the surface as their cells adjust to the new tank conditions. Thus, tank conditions might temporarily enhance surface biofilm.

Poor Circulation

Microbes prefer oxygen-rich water surfaces in mature tanks with weak circulation and gaseous exchange.

The slime further reduces surface exchange, creating a vicious cycle.

Poor Location

Aerosols and scented mists have to end up somewhere. They may also form a layer on the water in your aquarium.

Cooking grease may gather on the surface of your fish tank if it is too close to your kitchen.

Relocate your aquarium as far away from these toxins as possible.

Avoid this by locating your aquarium appropriately before installing it.

Pumps and Filters with Oil Residue

It’s a common practice to apply a very thin layer of oil over the working components of filters and pumps to keep them lubricated.

And it doesn’t even account for the other oils that were used up in production but discarded.

Cleaning the filter beforehand will reduce the amount of oil released into the aquarium.

How to Reduce Protein in Aquarium?

Oil slicks are especially dangerous in aquariums with no water circulation.

Water will churn and swirl when there is a continuous movement of the water, particularly agitation on the surface of the water.

And while it does so, it mixes and disperses the minute quantities of protein, which are finally eliminated by water changes and filter rinsing.

Here are some recommendations to reduce protein content in the aquarium.

Monthly Water Replacement

We can keep the water clean and fresh by replacing it once a month, especially if your aquarium has algae.

For regular water changes, it’s recommended that you only change out a third of the water in your tank at any given time.

You can do monthly water changes on your aquarium by obtaining a water-changing system that comes with all of the necessary supplies.

Introduce Algae Feeders

If you add certain fish and marine creatures that can aid in the reduction of algae in your tank, they can assist in keeping it under control.

With crabs, fish, shrimp, or other filter feeders in your tank, the waste in the tank will supply nutrients to your algae feeders.

You may explore these algae feeders: Dwarf bush nose pleco, Rubber nose pleco, Chinese algae eater, and Otocinclus catfish.

Restrict Food Supply

Some of the muck in your tank might be feces or uneaten fish food.

This debris can not only fog your tank but can also stimulate the growth of algae. Moreover, as a fish breaks down its meal, its digestive tract naturally creates oils and proteins.

And when your fish lets lose its bowels, defecation contains oils, which float to the top. And a slick of oil develops.

If you observe additional food floating in your tank, feed your fish only once a day or in lesser amounts.

Control Light Conditions

Photosynthesis makes algae flourish.

Keep your tank lighting on for less than 8 hours a day. This mimics natural light and prevents bacteria and algae growth.

You may turn on your light while at home or during the day and turn it off at night.

What Does a Protein Skimmer Do For an Aquarium?

Protein Skimmers are devices that are often utilized in saltwater aquariums to remove organic waste, such as fish feces, undigested food, and proteins. We can also use protein skimmers in freshwater aquariums.

Disease-causing parasites and bacteria thrive in unclean, protein-rich water.

These microorganisms depend on the very pollutant that the protein skimmer is designed to eliminate for sustenance.

Placing a protein skimmer in your aquarium will lessen the risk of disease spreading to your fish and corals.

Secondly, protein skimmers aid in algae controls by collecting debris before it can decompose into phosphates.

Lastly, protein skimmers help coral thrive by eliminating harmful substances from the water. Reduced levels of pollutants in the water increase the amount of light reaching your corals.

Do Freshwater Aquariums Need Protein Skimmers?

In order to keep the water clean, protein skimmers use a process called foam fractionization to seek actively and remove protein from the water.

Surface tension attracts dissolved organic molecules to micro-bubbles as they spin.

However, water salinity directly affects surface tension. Due to greater surface tension, bubbles and DOM attract better in saltwater.

Therefore, regular water changes are necessary to rid a freshwater aquarium of dissolved organic matter.

Unless the water in a freshwater aquarium has an extremely high concentration of protein, protein skimmers will not perform very well.

When used with freshwater, the physical principles that allow protein skimmers to efficiently extract protein from saltwater are ineffective except for increasing the oxygen saturation of water.

Do I Need a Protein Skimmer For Fish Only Tank?

The presence of fish alone is not sufficient justification for the installation of a protein skimmer.

However, protein skimmers operate more effectively in a tank containing saltwater rather than freshwater.

A protein skimmer isn’t necessary unless you’re maintaining a Nano reef aquarium.

And a protein skimmer is unnecessary if your aquarium already has a filtration system in place.

However, investing in just one will always pay off.

The time saved from not having to change the water in your tank as often is a direct result of using a protein skimmer.

You’ll have more time on your hands and be able to keep your fish less stressed if you don’t have to do water changes as often.

They can also boost oxygen levels, prevent the buildup of algae, and neutralize biological toxins.


Protein skimmers are a fantastic piece of equipment for saltwater aquariums; however, the results they provide in freshwater aquariums are not quite as impressive.

Regularly changing the water in a freshwater aquarium is the only method to rid the tank of any dissolved organic debris that may have accumulated.

As the tank owner, it is your duty to ensure that there are no protein films on the inside of the tank at all times.

Follow the methods and precautions in this article to remove an oil slick or protein film from your freshwater aquarium and have a healthy ecosystem for a longer time.

Leave a Comment