The 10 Best Protein Skimmers to Buy in 2025

Protein Skimmer Buyer’s Guide

If you’re feeling a bit bewildered by the protein skimmer and are struggling to comprehend what you need to purchase and why, you’ve come to the right place. In this in-depth buyer’s guide, we’ll explain exactly what a protein skimmer is, how it works, who should buy one, and its primary benefits.

We’ll also cover the different types of skimmers and provide information on installing and maintaining the device, as well as a lengthy F.A.Q.

The Protein Skimmer Explained

The protein skimmer is a kind of mechanical filter that removes unwanted organic material from your aquarium. These compounds, which include toxins, bacteria, waste products, and chunks of uneaten fish food, will eventually break down and ruin the water quality of your tank through excessive nitrate and ammonia content as well as algae growth.

Therefore, installing an effective protein filter will safeguard the health and well-being of your beloved marine animals. And as a neat little bonus, you’ll enjoy clearer and cleaner looking water as well.

How a Protein Skimmer Works

The device is called a “protein skimmer” because it uses a process known as the “polarity of proteins” to remove organic compounds from a water source. The process works via a reaction chamber that creates lots of tiny little bubbles, which the protein particles of nearby organic compounds fuse onto and float to the surface. Once there, the organic matter is filtered through a collection cup.

The best protein skimmers enhance the process by using a needle wheel impeller, A.K.A a pinwheel, to cut the bubbles into smaller bubbles, thus improving the polarity of proteins process.

Who Should Buy a Protein Skimmer

Novice aquarists might ask themselves: “Do I really need a protein skimmer for my tank?” While protein skimmers can help maintain a clean and healthy living environment for your beloved aquatic pets, they’re not a necessity for every aquarium.

Basic freshwater setups with common species of fish don’t require a protein skimmer, strictly speaking. It’ll still help keep the water clean and clear, but most freshwater fish and invertebrates can withstand the low nitrate levels that result from having organic matter floating around in the tank.

Saltwater tanks, on the other hand, absolutely do need a protein skimmer installed, especially once coral comes into the equation. Even minute levels of ammonia and nitrates will put a tremendous amount of stress on most marine species, eventually causing them to go belly up.

The Benefits of Installing a Protein Skimmer

Still unsure whether a protein skimmer is a worthwhile investment for your aquarium? Let’s take a look at some of the key advantages of getting one installed.

Protein Skimmers Lower Nitrate and Ammonia Levels

The main aim of a protein skimmer is to prevent the build-up of ammonia and nitrates caused by floating organic compounds, which can be deadly to larger fish (especially saltwater species) and coral.

Protein Skimmers Reduce Maintenance

As protein skimmers inhibit the growth of algae, you’ll spend less time trying to clean the green muck out. And as you’ll have less algae climbing the glass walls of your tank, you’ll enjoy a better view of your beautiful marine creatures.

Protein Skimmers Cleanse the Water

As a protein skimmer uses bubbles to push organic material to the surface, you’ll be left with lovely crystal clear water in the tank. No more stressing about leftover food flakes and fish waste floating around in the water.

Installing Your Protein Skimmer

Protein skimmers can be installed in three different ways, each of which is intended for a specific size or shape of tank. Choosing the correct type of protein skimmer is essential; otherwise, it simply won’t work on your set up.

Hang on Back (H.O.B.)

As you’ve probably inferred from the name, hang on back (commonly known as H.O.B.) protein skimmers are built to hang off the back end of your tank, which is perfect for setups that don’t have a sump. Note that H.O.B. protein skimmers are suitable for smaller tanks under a 100-gallon capacity, including nano tanks.

The system is positioned on the back rim of the tank, in much the same way you would install a power filter.

In-Sump

In-sump protein skimmers are designed to operate within the sump, a special filter primarily used for reef or marine aquariums. In-sump filters vary significantly in price, size, and features, with the more advanced models used in state-of-the-art aquariums for public display.

Smaller and more affordable in-sump protein skimmers cater to domestic and hobby aquarists.

In-Tank

In-tank protein skimmers are the smallest of the lot, typically designed for use inside nano tanks. Although they aren’t nearly as powerful as the abovementioned options, in-tank skimmers do an excellent job at cleaning smaller tanks with a modest amount of floating organic matter.

As you’d expect, in-tank skimmers do not require a sump to operate. As they take up precious room inside the tank, we recommend opting for an H.O.B. or in-sump skimmer instead.

Protein Skimmer Types

Regardless of how the device is installed, the skimmer itself will come in one of four varieties, each of which has its own distinct pros and cons.

Needle Wheel Impeller Skimmers

Needle Wheel (A.K.A impeller) skimmers are widely regarded as the crème de la crème of the protein skimmer industry, offering the most effective method of filtering out the contaminants of your tank. The skimmer directs air towards the impeller (the rotating component of a centrifugal pump) to create bubbles. The impeller has a tiny needle wheel that slices the air bubbles up to make even smaller bubbles, thus enhancing the effectiveness of the polarity generated

Impeller skimmers are easy to run as they don’t require a powerful pump to operate. However, they do tend to break down more often than other skimmer types, so if you’re not prepared to monitor the status of your aquarium, you might want to give these a pass.

Nonetheless, impeller skimmers are easily the most potent and popular option in the modern age, which is why we recommend these almost exclusively on our list.

Countercurrent Skimmers

The old school countercurrent skimmers use wooden air defuses and a heavy-duty air pump to produce large volumes of foam, thus optimizing the polarity of the process of the protein.

On the downside, they require quite a bit more maintenance than other skimmer types. Firstly, you’ll need to regularly switch out the air stones, perhaps as often as every two months if there’s a large amount of organic material in your tank. You’ll also need to monitor and repair the air pump diaphragms (rubber seals), as the system will stop functionally completely should they fail.

Countercurrent skimmers are somewhat outdated these days, now rather redundant thanks to the impeller needle wheel.

Venturi Skimmers

These use a mechanism called a “venturi injector” to create a large volume of air bubbles, which makes them a popular option for aquarists with high filtration needs. Although they’re small in size, you’ll need a powerful pump for these skimmers to function at their peak.

The best venturi skimmers come with a special spray head design that increases the volume of air in the water, thus resulting in more bubbles (and a cleaner tank). Venturi skimmers are generally favored by the owners of large scale operations like fish farms and public aquariums.

Downdraft Skimmers

Downdraft skimmers function by using a jet to spray water at a high velocity into a series of bio balls within a column. As the bubbles pass through the bio ball column, they enter into the sump, which deflects them in an upward motion to create foam.

The process requires water to be pushed further than most other skimmer types as it needs to pass through the column before bubbles can appear. Therefore, you’ll need a bigger pump to operate the system, and the skimmer tends to be bigger overall.

Installing a Protein Skimmer

Most protein skimmers intended for domestic use are designed to be easily installed by the ‘Average Joe’ with no specialist skills. Because every protein skimmer is different, the easiest way to work out how to set yours up is by consulting the instruction manual.

If you’ve lost your manual (or can’t understand it), try searching YouTube for instructional videos. The most popular protein skimmers all have at least one tutorial to guide you through the installation and maintenance process.

Maintaining a Protein Skimmer

A decent protein skimmer from a reputable brand, such as those we recommend on our top 10 list, will usually work without breaking down.

Nonetheless, the aquarist does need to perform periodic maintenance in terms of manually cleaning out the collection cup. If you’re the kind of person who might forget to carry out this essential task, then opt for a protein skimmer with a larger collection cup, as these can be emptied less often. Better yet, go with a model that has a collection cup drainer, which automatically siphons the organic gunk into a separate reservoir.

We recommend doing a more in-depth maintenance every six months or so, which involves disassembling the unit and cleaning all its components. Aim to replace rather than clean the plastic tubing, as it always starts to degrade after a while.

You can clean the parts by soaking them in hot water for an hour, then gently scrubbing them with a soft brush. Rinse each piece again before reassembling the unit.

Protein Skimmer F.A.Q.

If you’ve made it this far and still have questions about the protein skimmer, there’s a good chance you’ll find them below.

Do Protein Skimmers Remove Nitrates?

A common misconception is that a protein skimmer will remove nitrate from the water. However, that’s not exactly the case. Instead, the tiny bubbles lift organic material to the surface before they break down into nitrates.

Therefore, it would be more accurate to say protein skimmers prevent the accumulation of nitrates.

Do Protein Skimmers Remove Phosphates?

Not exactly.

Reactive phosphates stimulate algae growth, while inorganic phosphates interfere with coral growth by inhibiting the formation of a healthy calcium carbonate skeleton. Protein skimmers can’t remove either type from your system, but they can prevent them from accumulating by reducing the level of organic compounds in the water. Many organic materials contain phosphorous, which breaks down into phosphate.

Therefore, as is the case with nitrates, a protein skimmer can help prevent the build-up of phosphates.

Do Protein Skimmers Remove Ammonia?

Protein skimmers won’t remove ammonia from the water in your tank, but they can prevent it from accumulating in the first place.

Uneaten fish food and solid waste will eventually decompose into ammonia after being broken down by bacteria. Removing these organic elements from the water before this decomposition occurs will stop the ammonia content in your water from increasing.

Will a Protein Skimmer Help With Algae?

Yes.

Algae needs to feast on nutrients such as nitrogen and phosphorous to survive. Organic compounds floating in the water will slowly release these nutrients over time, thus allowing the algae to bloom.

Prohibiting the build-up of organic material in the water via a protein skimmer will starve algae of their food source and significantly inhibit their growth. Although a protein skimmer won’t totally remove algae from your aquarium, it will help bring the problem under control.

Should I Run My Protein Skimmer All the Time?

Yes.

Because coral, fish, algae, and bacteria are constantly releasing organic matter into the water, you’ll need to leave your protein skimmer on 24/7 to compensate.

Letting the skimmer run continuously will remove organic material as soon as it enters the water and, therefore, reduce the level of ammonia, nitrates, and phosphates in your tank—all of which are bad for marine animals. Switching it off periodically will allow these elements to accumulate and compromise the well-being of your pets.

Are Protein Skimmers Noisy?

Protein skimmers do make a faint humming sound, which can be annoying when it’s located in the bedroom, and you’re trying to sleep. To rectify the issue, you could try placing a foam matt under the skimmer to reduce the noise-emitting vibrations. Also, check all the parts of the pump are working correctly, as these can make an awful racket when damaged.

Loud gurgling or splashing sounds aren’t normal, however, and can usually be fixed. Try tweaking with the airflow or putting a foam block underneath to reduce the splashing sound.

Why Is My Protein Skimmer Overflowing?

Some protein skimmers tend to foam up and overflow, especially if not configured correctly. Consult your instruction manual to learn the proper way to set up the device.

Overflowing often occurs when the skimmer collection cup is too low. Moving the cup up higher may cause the foam to become fluffier and drier as it forces the excess water to drain away.

You could also try turning down the air adjustment valve. It won’t have an immediate effect, so come back in 15 minutes to see whether that has helped. If necessary, turn it down a little more and reassess again.

Why Isn’t My Protein Skimmer Creating Foam?

If you’ve just set up a brand new protein skimmer in your tank, you’ll need to wait for a while for the system to “break-in.” The process generally takes a few days, by which time you should start seeing foam bubbles appear. Once it’s started working correctly, you can begin fine-tuning (dialing in) the settings if required.

Note that the amount of foam produced isn’t constant—skimmers in clean tanks will make minimal foam, while those in tanks with a high level of organic content create huge spurts. A recently deceased fish or a large-scale algae die-off will cause an increase in the organic matter content of your tank and lead to more active bubbles.

Do Protein Skimmers Oxygenate Water?

Yes, to an extent.

Protein skimmers create micro-bubbles, which enhance the level of oxygen as they agitate the surface of the water. Note that the degree of oxygenation is relatively low compared to a pump, which circulates water throughout the entire system.

Why Aren’t Protein Skimmers Very Effective in Freshwater?

Protein skimmers work by creating microbubbles that latch on to organic matter and draw it to the surface. In saltwater, dissolved organic matter creates a stable and semi-rigid structure around the bubbles, which we call “skimmate” foam.

In freshwater, however, a difference in surface tension between the water and the organics inhibits this process, which makes protein skimmers far less effective. For this reason, aquarists generally don’t bother using skimmers in freshwater unless there’s a higher-than-usual density of organic matter, such as in fish farms or crowded public aquariums. To clean out unwanted organic compounds in freshwater, most people opt for a frequent water change instead.

Final Thoughts: The Best Protein Skimmers

Now that you’re a verified protein skimmer expert, it’s time to peruse our recommendations and purchase one for your aquarium. Remember to factor in our top considerations to determine what features are most important to you.

With the right protein skimmer in place, you’ll be able to reduce toxins and create a healthy environment for your adorable aquatic pets to thrive. Couple that with crystal clear water and a distinct absence of algae, and it’s easy to see why a quality protein skimmer is a worthy investment for every avid aquarist.