This is why you use a Surface Skimmer for your aquarium

surface skimmer

If you want to keep your aquarium clean, you should also have a so-called surface skimmer. This is a practical helper in maintaining the water quality and removing the skin.

What is a surface skimmer?

A surface skimmer (also called aquarium skimmer) is a small, motor-driven filter for the aquarium.

Its inlet is located directly on the surface of the water.

The aquarium water that is located on the skimmer flows through the sucker together with the impurities. If there are any plant remains in it, a special container prevents them from getting into the pump wheel. The latter is best checked regularly and, for example, during normal water changes, and cleaned if necessary.

The most common use of surface skimmers is therefore to remove scum from the aquarium.

What is surface scum?

Surface scum is a kind of biofilm of microorganisms that is on the surface of the water in an aquarium.

It can also attach itself to solid objects such as stones. The scum is, so to speak, the boundary between the water and the air.

  • It consists of a wide variety of microorganisms such as algae, bacteria or yeast. These accumulate there because they find ideal living conditions.
  • Scum is also favored by dust particles from the air, among other things because these have a special surface tension and therefore cannot sink in the water.

In addition, there are mainly substances on the underside of the water surface that are lighter than water, but cannot easily escape into the air. There are aquarists who simply find the skin unsightly. In addition, this can interfere with and reduce the incidence of light.

surface skimmer

How to remove surface scum: This is how it works!

What exactly is the biofilm? It consists of bacteria.

Bacteria emerge or become visible when, for example, too much or incorrectly fed or fertilized is used.

This bacterial skin is actually not dangerous. It becomes a huge problem if the entire surface of the water is really “tight” thereby restricting a proper gas exchange between the water and the air and CO2 can accumulate in the aquarium.

You should maintain the surface of the water regularly to make sure there is no buildup of surface scum. If left unchecked, the biofilm can also reflect a lot of the light, which does not necessarily contribute to plant growth.

It is important to temporarily reduce the feeding and / or fertilization a little and manually / mechanically remove the scum.

Instructions: Remove scum – this is how it works:

In the Video below, you can see how easily and quickly you can remove the scum with a paper sheet or paper towel.

How to remove aquarium biofilm with a paper sheet

  • Pick up directly from the surface of the water with kitchen paper
  • Point the filter outlet at the surface of the water so that the skin can be seen to tear open (it doesn’t matter if it is floating around in the aquarium)
  • If necessary, vacuum as much as possible when changing the water
  • Consider using a surface skimmer!

How does a surface skimmer work?

The individual models are partly structured differently, but the basic functionality is always quite similar.

Inside the surface skimmer there is a small pump motor which, similar to an internal filter, continuously draws in the water.

This also breaks the surface film. The surface skimmer is attached to the panes in the pool either with suction cups or with special struts.

Some models also have a floating protective ring. This can adapt itself completely independently to the water level of the aquarium.

The protective ring also prevents fish and other pool inhabitants as well as somewhat coarser plant residues from being accidentally shredded by the surface skimmer.

So if you want to be on the safe side, you should choose a model that has one. Some aquarists also optimize this special protective device with filter sponges or with particularly fine grids. This prevents shrimps and other small aquarium inhabitants from getting into the filter.

Basic structure of the surface skimmer

The heart of the surface extractor is the pump motor, which makes it possible in the first place to suck in water continuously, like an internal filter, and thus break the water surface film.

Depending on the model, the holder of the surface skimmer consists of suction cups or struts on which the “filter” is attached to the aquarium pane, so to speak.

The best surface skimmers have a floating protective ring at the filter inlet, which continuously adapts to the water level. There are also models in which the filter inlet does not adjust itself. We find the latter to be very handy.

The protective ring around the filter inlet of the aquarium surface skimmer serves to:

  • Protect coarse plant residues
  • Protect the aquarium inhabitants from “shredding” or being sucked in

Some aquarium owners tune this protective device with filter sponges or fine grids to prevent curious shrimp from voluntarily crawling into the filter.

HOW TO: DIY Aquarium Skimmer

Does an aquarium surface skimmer make sense?

Is such a surface skimmer useful or really necessary, you ask yourself? To be honest, these accessories aren’t really necessary.

An internal or external filter, which moves the surface sufficiently and can therefore break through the scum, also makes a major contribution to keeping the water surface clean.

However, an additional surface skimmer makes sense for aquariums that are less moving. This is mostly used to declare war on the skin (a whitish, milky film of bacteria on the water surface).

Surface skimmer such as the Eheim Skim 350 are very popular with aquascappers. It is often used in aquariums without a cover, where a scum would be noticed immediately. In addition, it is also practical to have the freshly cut plant shoots collect at the inlet of the surface skimmer without taking nets forever.

NOTE: Surface skimmers are used permanently as the sole filter in nano aquariums. For example, the ADA Vuppa can often be seen as the sole filter in small aquascaping tanks.

Fluval Aquarium Surface Skimmer

Advantages of surface skimmers

  • Fast and effective method for removing dead skin
  • Removes almost all particles on the surface including plant residues
  • Most models are easy to clean

Disadvantages of surface extractors

  • Additional costs / acquisition costs
  • Should e.g. cleaned with the water change


With a surface skimmer, the scum on the water surface of an aquarium can be removed effectively and sustainably. There are different models, some of which have a practical swim ring.

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