Pro Tips On How to Get Rid of Protein Film in Fish Tank

Protein and oil film on the water surface in aquariums is a prevalent topic in aquatic forums.

Aquariums, especially their tops, tend to accumulate proteins in the form of a thick film. There are various reasons behind protein layers or greasy oil on the aquarium water surface.

This thin oil film is hazardous for your fish as it will become thicker over time, preventing them from reaching the water surface to breathe fresh air.

As an aquarist, you should know how to get rid of protein film in fish tanks.

How to Get Rid of Protein Film in Fish Tank?

Remove Protein Film in Your Fish Tank Immediately

Use Paper Towel: You can use a highly absorbent paper towel to remove the protein film. However, avoid using paper towels containing bleach and other harmful chemicals.

Take Advantage of Water Circulation: You can speed up the flow rate of water coming out from your filter. The circulation of the water will prevent protein and oil films from accumulating on the water’s surface.

Use Surface Skimmers: You can also use surface skimmers to minimize the formation of oil and protein films.

Deep Clean Your Aquarium


Aquarium filters are crucial in keeping your aquatic environment clean and suitable for your fish to survive. So, you should deep clean them to ensure they function optimally.

Step 1: Start by unplugging your filter.

Step 2: Then, remove debris using a mixture of white vinegar and water. You might consider replacing the sponge and sieve in your filter if necessary.

Step 3: Clean your tank filter with a soft toothbrush to remove algae and microbial buildup. Let your filter dry entirely in the air before putting it back.

Tank decor

You will also need to remove and wash any décor in your aquarium. Then, let them air dry before placing them back in your aquarium.

We recommend replacing the gravel lining your tank, although you can reuse it. But if you want to reuse your gravel liner, follow these steps:

Step 1: Gather the gravel, boil it in water, and wait three to five minutes.

Step 2: Strain it before letting it dry in the air.

Step 3: Once your gravel has dried and cooled, put it back into your fish tank.


Cleaning lights in your tank should also be included. Follow these steps to clean them quickly:

Step 1: Remove your tank lamps with bulbs.

Step 2: Then, clean the bulbs with a mixture of white vinegar and water in a 1:1 ratio.

Step 3: Let them air dry and put them back into your tank.


Step 1: Completely remove your old tank water. Then, fill the tank with clean water and add a bottle of white vinegar for each gallon of water.

Step 2: Leave this mix to soften your tank’s edges for about sixty minutes.

Step 3: Remove two-thirds of the mixture from your aquarium.

Step 4: Scrub inside your tank with a brush or soft towel.

Step 5: Rinse the tank with clean water at least two times.

Step 6: Leave your aquarium air dry. Then, put your décor, lights, and fish back in your tank.

What Causes Oil to Appear in Your Aquarium?

protein film in fish tank

There are many causes of a protein film


Your fish will inevitably release waste, and it is inevitable. The greasy the food you feed your fish, the more oily their droppings will be.

In addition, the natural digestive system of fish typically produces protein and oil during the breakdown of food.

So when they excrete feces, the oil in their feces will contribute to the production of protein film.

Oil From Your Hands

The pores on your hands naturally secrete oil. When dipping your hand in the tank water, this oil will form an oil film on the water’s surface.

So you should wash your hands thoroughly with soap before putting your hands in the aquarium.

Uneaten Food

The food you feed your fish usually contains some form of fat. So, when you feed the fish, the proteins and fats inside the food will float to the water’s surface.

If you overfeed your fish, the leftovers will continue releasing fat and protein, worsening the situation.

So you will probably want to limit foods high in protein and fat. Also, avoid overfeeding your fish.

Dead Fish

When your fish dies, besides producing an unpleasant odor, it will release oils and fats into the tank water as breaking down,

Pumps and Filters

The cause can also come from your new filter.

Pumps and filters often have a small amount of oil on their moving parts. In addition, they have other oils left over from the manufacturing process.

So you should rinse your filters before placing them in the aquarium.

Poor Aquarium Location

Placing your aquarium in the wrong place can also be a cause.

For example, if you place your aquarium too close to the kitchen, the grease in the air during cooking will settle on the water’s surface.


Are Oily And Protein Films Dangerous?

A small amount of oil will not harm your fish. However, your fish could suffocate if it builds up and forms a thick layer of oil on the tank’s surface.

How Long Does It Take to Clear the Protein Film?

Removing the protein film may take 10 to 15 minutes if you use a strong aerator or filter.

On the other hand, if you manually remove the film using a paper towel, it will take up to five mins, depending on the film’s thickness.

How Can You Distinguish the Type of Film?

Protein deposition: Darker in color and gives off gray or white hues.

Oil deposition: The seven colors of a rainbow are displayed.

Biofilm: Strong ammonia odor.

When Should I Replace the Water if I See Frequent Films?

We recommend changing your aquarium’s water every two to four weeks.

How Costly Is It to Maintain My Aquarium?

  • Saltwater fish tank: The maintenance costs range from $400 to $600.
  • Freshwater fish tank: The maintenance costs are between $100 to $200.


Oil and protein films are common and undesirable when it comes to aquariums. If left too long, they can become thicker and cause your fish to suffocate.

Fortunately, you can easily remove them by following our guide. Hopefully, this article was helpful to you!