OASE CrystalSkim 350 Aquarium Surface Skimmer

The OASE CrystalSkim 350 is a compact aquarium surface skimmer designed to remove the oily film, biofilm, floating plant debris and duckweed that can collect on the surface of your aquarium.

If your tank looks clear below the surface but develops a film across the top, the CrystalSkim 350 is an easy way to keep the water surface looking clean while helping maintain better gas exchange between the aquarium and surrounding air.

Suitable for freshwater and marine aquariums up to 350 litres, it is particularly useful in planted and aquascaped tanks where small pieces of plant material are often left floating after trimming.

Key Features & Benefits

• Removes surface biofilm, oily film and floating debris
• Collects fine plant trimmings after aquarium maintenance
• Helps remove unwanted duckweed from the water surface
• Supports better gas exchange by keeping the surface clear
• Adjustable flow lets you control the strength of the skimming action
• Floating intake automatically follows small changes in water level
• Integrated protective basket provides additional protection for small fish and shrimp
• Compact design takes up very little space inside the aquarium
• Suitable for freshwater and saltwater aquariums
• Designed for aquariums up to 350 litres

Why Use an Aquarium Surface Skimmer?

Even a well-filtered aquarium can develop a thin film across the water surface.

This film can be made up of proteins, oils, microorganisms, food residue and other organic material. It can make an otherwise clean aquarium look dull and, when heavy enough, can also reduce gas exchange at the water surface.

A surface skimmer continuously draws water from the very top of the aquarium, helping remove this material before it builds up.

The result is a cleaner-looking water surface with less manual skimming required.

Great for Planted Aquariums and Aquascaping

The CrystalSkim 350 is particularly useful in planted aquariums and aquascapes.

After trimming aquarium plants, small leaves and plant fragments can remain floating on the surface and can be difficult to collect with a net.

The CrystalSkim draws these fine pieces toward the skimmer where they can be collected, making cleanup after aquarium maintenance much easier.

Browse our aquascaping supplies for more planted aquarium equipment, tools and accessories.

Helps Remove Surface Biofilm

If you've noticed a cloudy, oily or rainbow-like film across the top of your aquarium, you're seeing a common form of surface biofilm.

The CrystalSkim continuously pulls water from the surface, helping remove this film rather than simply pushing it around the aquarium.

Keeping the water surface open also helps support normal gas exchange, which is important for fish, plants and the aquarium's biological processes.

Adjustable Flow

Not every aquarium needs the same amount of surface movement.

The CrystalSkim 350 allows the water flow to be adjusted so you can reduce or increase the skimming action to suit your aquarium.

This is particularly useful in smaller tanks or aquascapes where you may want effective surface cleaning without creating excessive water movement.

Floating Intake Follows the Water Level

One of the most useful features of the CrystalSkim is its floating intake ring.

The intake follows small changes in aquarium water level, helping the skimmer continue drawing water from the surface even as the level changes through normal evaporation.

This reduces the amount of adjustment needed between routine aquarium maintenance.

Designed With Small Aquarium Inhabitants in Mind

The CrystalSkim 350 includes a removable protective basket designed to reduce the chance of smaller aquarium inhabitants entering the skimmer.

This is useful in aquariums containing small fish or shrimp.

As with any powered intake, very small livestock should still be monitored and the skimmer should be positioned and adjusted appropriately for the animals in your aquarium.

Compact and Discreet

At approximately 36mm in diameter and 116mm high, the CrystalSkim 350 has a small footprint compared with many aquarium filtration products.

Its compact design allows it to sit discreetly against the aquarium glass without dominating the aquascape.

Two suction mounts hold the unit securely in position while still allowing it to be removed easily for cleaning.

Specifications

• Brand: OASE
• Model: CrystalSkim 350
• Suitable Aquarium Size: Up to 350L
• Flow Rate: Approximately 200–300 L/h
• Power Consumption: Approximately 4.5W
• Dimensions: 36mm diameter × 116mm high
• Cable Length: Approximately 2m
• Suitable For: Freshwater and saltwater aquariums
• Installation: Internal aquarium surface skimmer

What Does the CrystalSkim 350 Remove?

The OASE CrystalSkim 350 is designed to collect floating material such as:

• Surface biofilm
• Oily surface film
• Fine plant debris
• Small floating leaves
• Duckweed
• Other lightweight floating aquarium debris

Does the CrystalSkim Replace an Aquarium Filter?

No.

The CrystalSkim 350 is designed specifically to clean the water surface. It does not replace your aquarium's main biological and mechanical filtration.

Think of it as an additional piece of equipment that deals with material your normal filter may not easily collect because it remains floating on the surface.

For complete aquarium filtration, browse our aquarium filters and filtration range.

Cleaning and Maintenance

Like any aquarium intake, the CrystalSkim should be checked and cleaned regularly.

How often it needs cleaning will depend on how much biofilm, duckweed and plant debris it collects.

If the flow begins to decrease, remove collected debris and clean the sponge, intake and impeller as recommended by OASE.

Regular cleaning helps maintain consistent surface skimming performance.

Is the OASE CrystalSkim 350 Right for Your Aquarium?

The CrystalSkim 350 is a great addition if you regularly notice:

• An oily or cloudy film across the water surface
• Floating plant clippings after trimming
• Duckweed that is difficult to remove manually
• Debris collecting at the surface
• A planted aquarium where you want to keep the surface looking clean

Its compact size and adjustable flow make it particularly well suited to planted aquariums and aquascapes where you want effective surface cleaning without adding bulky equipment.

Browse more OASE aquarium products available from Aquaholics.

Frequently Asked Questions

What does the OASE CrystalSkim 350 do?

It removes floating material from the aquarium surface, including biofilm, oily surface film, duckweed and fine plant debris.

What size aquarium is the CrystalSkim 350 suitable for?

OASE recommends the CrystalSkim 350 for aquariums up to 350 litres.

Does the CrystalSkim 350 remove aquarium biofilm?

Yes. Removing surface biofilm is one of its primary purposes. It continuously draws water from the surface and collects the floating material.

Is the OASE CrystalSkim suitable for planted tanks?

Yes. It is particularly useful in planted aquariums because it can collect fine leaves and plant fragments left floating after trimming.

Can the CrystalSkim 350 remove duckweed?

Yes. OASE specifically identifies duckweed as one of the floating materials the CrystalSkim can help remove from the aquarium surface.

Is the flow adjustable?

Yes. The water flow can be adjusted so the skimming strength can be matched to the aquarium.

Can I use the CrystalSkim 350 in a marine aquarium?

Yes. OASE lists the CrystalSkim 350 as suitable for both freshwater and saltwater aquariums.

Does the CrystalSkim replace my main aquarium filter?

No. It is a dedicated surface skimmer and should be used alongside appropriate biological and mechanical aquarium filtration.

Is the CrystalSkim safe for shrimp and small fish?

The unit includes an integrated protective basket designed to provide additional protection for small aquarium inhabitants. Very small livestock should still be monitored around any powered aquarium intake.