Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (2023)

If scraping algae off your glass makes you sad, consider getting an algae eater for your aquarium.

I'm not saying that your algae eater will keep your tank perfectly clean and free of algae, but they certainly help keep the green stuff under control.

And some of the best freshwater algae eaters are fascinating to watch and fun to keep.

Algae eaters come in a variety of sizes, and this article will discuss which freshwater algae eaters are best for aquariums from 2 gallons to 100+ gallons.

Size, aesthetics and algae eating efficiency are the main factors considered in this article, but choosing the right algae eater for you will also depend on what fish you plan to keep with your algae eater.

Table of contents

The best freshwater algae eaters

Most of the fish and invertebrates listed in this article will do well in a community aquarium, but some are better kept alone or exclusively with conspecifics.

Choosing the right algae eater isn't just about selecting the right size fish for your tank, it's also about choosing an interesting and enjoyable fish to keep.

1. Otocinclus

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (1)

Temperature: 74-80 F (23.33-26.67 C)

pH: 6,5-7

Tank mate: 5-20 Liter

My overall top pick for the best algae eater is the personal Otocinclus.

Also known as a Dwarf Sucker, Otocinclus combines algae-eating efficiency with a small body size, making them ideal for nanotanks.

Otocinclus grows to a maximum size of about 2 inches and fills the need for a small algae eater in 5 gallon to 20 gallon tanks.

interesting,Found in the wild, Otocinclus live in social groups consisting of thousands of individual fish.

Otocinclus are shy fish and should be kept in groups of 5 or more to reduce stress.

But keeping a few Otocinclus in a 5 gallon is certainly doable, especially if the tank only houses a single fish, such as a betta fish, or is a dedicated shrimp tank.

Otocinclus, or "Otos," are peaceful fish and therefore make excellent tank mates for a variety of other tropical community fish.

While Otos feast on the available algae in your tank, it is important for the health and longevity of your fish to provide a high-quality algae wafer to supplement their diet.

When choosing an Oto for your aquarium, ask if the Otos on display are wild caught or captive bred.

And ask how long the fish has been in the store.

Otos that have survived 2 weeks or more in a fish store have a much better chance of survival in your home aquarium.

Purchasing captive-raised fish is vital to preserving wild populations, and in the case of Otos, the methods used to catch them in the wild too often result in fish dying within days of being killed by a aquarist have been brought home.

So, to save your frustration and wild Otocinclus populations, try to find well-established captive-bred Otos for your tank.

2. Bristlenose catfish

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (2)

Temperature: 72-80 F (22.22-26.67 C)

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pH: 6,5-7,5

Tank mate: 15-25+ Liter

Bristlenose catfish, also called bristlenose plecos or bushynose catfish, are of the genus Ancistrus, and are therefore not true"plecostomen"like the regular pleco.

Bristlenose catfish are so named because the front of their snouts (for lack of a better word) are covered with fleshy branches or tentacles.

Male bristlenose usually have larger tentacles extending over the head, while females have smaller tentacles around the snout.

Bristlenose catfish are great algae eaters and can quickly remove algae from glass, decorations and driftwood.

The beauty of bristle catfish, compared to the common pleco, is their reasonable size.

Bristlenose catfish grow up to 6 inches (15 cm) in length, but many stay about 4 inches (10 cm) in home aquariums.

Common plecos, on the other hand, can grow over 12 inches (30 cm) in length and will quickly outgrow most tanks.

Juvenile bristlenose catfish are perfect algae eaters for aquariums between 15-25 gallons, but need an upgrade once they reach their full size.

3. Regular Pleco

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (3)

Temperature: 72-80 F (22.22-26.67 C)

pH: 6,5-7,5

Tank mate: 100+ Liter

The common pleco (Hypostomus plecostomus - say that 5 times fast) is what many consider to be the quintessential algae eater in home aquariums.

All too often these plecos are sold as babies and look like the perfect addition to a newly set up 10 gallon tank.

But the unsuspecting buyer will eventually discover that these plecos become monsters pretty quickly (range between 15 and 24 inches), and really need to live in tanks or ponds over 100 gallons.

Common plecos are best avoided unless you have or plan to have a giant aquarium.

That said, regular plecos are stunning to watch.

They have armor, big eyes and look like a dinosaur.

If you have the space, a common placo is an excellent algae eater, otherwise check out the bristle catfish, which remains much more reasonable in size.

One thing to note is that while plecos are known to be algae eaters, they are also opportunistic and will eat small fish and shrimp given the chance.

4. Hillstream Loach

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (4)

Temperature: 68-76 F (20-24.44 C)

pH: 7-8

Tank mate: 20-40+ Liter

Hillstream loaches (of the genusSewellia) are one of the most unique looking algae eaters available in the aquarium hobby.

The body of a hill stream loach is surprisingly flat, giving it an otherworldly appearance (think facehugger).

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This helps the fish stick to rocks and wood, even in environments with a strong water current, such as a stream.

In the wild, Hillstream Loaches live in fast-flowing, oxygenated, tropical rainforest streams in Asia.

In home aquariums, the water flow is often much weaker than in their native habitat.

Thus, a common question about hill loaches is whether these fish can be kept in low-flow aquariums, with basic filters such as a hang-on-back or sponge filter.

The answer is that mountain stream loaches seem to be most active in high flow tanks where the total water turnover is about 10-20 times per hour.

Many aquarists find they can keep mountain stream loaches in tanks with less current, but it's unclear if the loach thrives or simply survives in these conditions.

Ideally, a tropical fish's native habitat would be mimicked as much as possible by the home aquarists, so it's best to provide a high flow section of your tank (with a powerhead), and this will likely reduce stress levels in your fish .

Hillstream Loaches have been known to pop out of aquariums so a lid is recommended.

Although these fish are voracious algae eaters, it is important to supplement their diet with spinach leaves and a quality algae wafer.

5. Amano Shrimp

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (5)

Temperature: 70-80 F (21.11 - 26.67 C)

pH: 6.5-8

Tank mate: 2-100+ Liter

My fifth pick for the best algae eater is the Amano Shrimp.

These freshwater shrimp are fantastic algae eaters and are also fascinating to watch as they run around the tank looking for bits to eat.

Made famous by world renowned aquascaper Takashi Amano, these shrimp are extremely popular among planted tank enthusiasts and aquascapers for their ability to eat algae and also for the natural aesthetics these shrimp provide.

If your goal is a natural style aquarium, these shrimp are the perfect choice.

Check out my articles aboutplanted tanksInaquascaping tips for beginnersif you are planning to set up an aquarium for these beautiful shrimp.

Amano shrimp can grow to a good 2 inches, making them excellent tank mates for fish that may eat smaller shrimp species.

6. Cherry prawns

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (6)

Temperature: 72-80 F (22-27 C).

pH: 6.5-8

Tank mate: 2-100+ Liter

Cherry Shrimp (Neocaridina davidi) are freshwater shrimp named for the bright red color of their carapace (shell).

This species of shrimp actually comes in a wide variety of colors, including green, blue, orange, and yellow, but the common name "cherry shrimp" has stuck, which is why, regardless of color, this freshwater shrimp is often referred to as a cherry shrimp.

Cherry shrimp are excellent algae eaters and a large group can quickly clear out a small tank.

While they tend not to eat hair algae, they make an excellent cleanup crew and are perhaps the most visually stunning algae eater on this list.

Cherry shrimp, unlike their crystal shrimp cousins, are about as easy to care for as tropical community fish.

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They appreciate stable water conditions, but can tolerate minor fluctuations in parameters (at least in my experience).

The trickiest part about keeping cherry shrimp is choosing suitable tank mates for them, as many fish view them as a snack.

If you would like to learn more about tank mates for these shrimp or learn more about other freshwater shrimp species, please visit myultimate shrimp tank guide.

7. Siamese algae nets

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (7)

Temperature: 75-80 F (23.89 – 26.67 Celsius)

pH: 6.5-8

Tank mate: 20+ Liter

The Siamese algae (typischCrossocheilus langei;Crossocheilus siamensis; ofCrossocheilus oblongus) is perhaps best known as one of the few fish that eats black beard algae (or brush algae) and hair algae.

If you've never battled black beard algae (*shudders*), count yourself lucky, it's really hard to eliminate.

But Siamese algae eaters can help you beat it.

Some individual fish seem more motivated than others to eat the stuff, but if you're lucky enough to find a true Siamese algae eater, he/she will help rid your tank of black beard algae for good.

The main downside to these fish is finding the real deal, as they are often mislabeled and misidentified in fish stores.

Instead of bringing home a Siamese Algae Eater, many unsuspecting aquarists bring back a Flying Fox (Epalzeorhynchos kalopterus).

To make things even more confusing, Siamese algae eaters are sometimes referred to as "Siamese Flying Foxes," meaning any fish labeled "Flying Fox" in the fish store is suspect.

Are bestan also valse Siamese algeneters (Garra cambodgiensis), as well as Chinese algae eaters (Gyrinocheilus aymonieri), adding additional confusion.

If you want to dig deeper into the differences between these similar looking fish, check outTheKrib's article on algae eaters.

The best way to identify a true Siamese algae eater is to make sure the fish has it:

1) a solid black stripe extending from its tail to the tip of its nose (the stripe divides the center of the tail);

2) Translucent fins, especially the dorsal fin; And

3) No red discoloration along the tips of the fins.

Siamese algae eaters are perfect for planted aquariums, eating algae from plant leaves and perching on top of larger plants in a way that is unusual for freshwater fish.

If you can find one and have a tank that is 20 gallons or larger, get one.

8. Mysterious Snail

Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons) (8)

Temperature: 70-80 F (23.89 – 26.67 Celsius)

pH: 6.5-8

Tank mate: 3-20+ Liter

Snails are often seen as a nuisance in aquariums, and the little ones that seem to take over your tank after introducing a new plant certainly live up to that reputation.

But some of the best algae eaters in aquariums are snails.

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And some of the best algae-eating snails are "mystery snails."

Mysterious snails (Pomacea brigesii) are a very underrated algae eater, they are interesting to watch and make peaceful tank mates for a wide variety of tropical fish.

During the day these snails often seem to be doing nothing, but at night they will cruise around your tank cleaning algae from plant leaves, glass and decor.

At just over 2 inches in diameter, mysterious snails are perfect algae eaters for tanks where aquarium shrimp would be gobbled up.

A large mysterious snail is usually left alone by most aquarium fish.

There are exceptions, so keep an eye on your snail and remove it if your fish starts knocking it off the glass or trying to gouge its eyes out.

But most of the time, your mysterious snail is left alone to slowly but surely remove algae from your tank.

Providing your snail with supplemental food, such as algae wafers, is a good way to ensure its survival.


The algae-eating fish discussed in this article are not the only algae eaters in existence.

Numerous fish will pick algae, although they are often much less efficient than the fish and invertebrates mentioned above.

For example, mollies often pick algae off the glass and decor.

But mollies are much less efficient than a dedicated algae eater like an Otocinclus, or even a group of cherry shrimp, so they didn't officially make it onto my best algae eater list.

Pest aquarium snails, such as Pond Snails, also eat algae, but most aquarists aren't interested in an aquarium full of tiny snails, so they didn't make my list either.

If you have a snail problem in your aquarium, read my article about ithow to remove aquarium snails.

As for "suckerfish," the common pleco and bristlenose catfish aren't the only species that eat algae.

A wide variety of plecos and sucker catfish exist, many with fascinating colors and fin shapes, but they tend to be more expensive and harder to find.

Fortunately, the fish in this article are relatively common and may be easy to find depending on where you live.

If you're thinking about adding an algae eater to your tank, I hope this article has given you a better idea of ​​which fish to choose.

If you're thinking about setting up a small tank, such as a 5 gallon tank, and need more ideas on what fish can live in small tanks, check out my article on thebest fish for a 5 gallon tank.

Or if you have a 10 gallon tank, check out my article on thebest fish for a 10 gallon aquarium.

Stay zen as always.



Best Algae Eaters for Freshwater Aquariums (from 2-100+ Gallons)? ›

An adult common pleco requires a 150-gallon tank, minimum. However, as juveniles, they can be kept in smaller aquariums as long as there is a plan in place to move them as they get bigger. Consider at least a 55-gallon tank to allow a young pleco room to grow.

Can I put a pleco in a 2.5 gallon tank? ›

An adult common pleco requires a 150-gallon tank, minimum. However, as juveniles, they can be kept in smaller aquariums as long as there is a plan in place to move them as they get bigger. Consider at least a 55-gallon tank to allow a young pleco room to grow.

What is the easiest algae eater to keep? ›

A snail of many names, the Apple Snail (also known as the Golden Mystery Snail, Golden Inca Snail and Yellow Snail) are effective algae eaters and eye-catching tank inhabitants. Golden yellow in colour, these beautiful snails are easy to take care of and prefer sharing their space with other non-aggressive tank mates.

What is the minimum tank size for an algae eater? ›

An adult Chinese Algae Eater needs a minimum tank size of 50 gallons (≈ 200 liters) in order to feel comfortable and secure. A 30-gallon tank may be suitable for a juvenile fish. It can also work for an adult one if it's the only tank occupant.

What fish can live happily in a 2.5 gallon tank? ›

Cherry, Checkerboard, and Golden dwarf barbs are small enough to live in a 2.5-gallon tank.

How big of a tank do you need for 2 plecos? ›

Housing Requirements for Plecostomus

For example, the common pleco, Hypostomus plecostomus, can grow to over 12" and will eventually need an aquarium of at least 75 gallons, while Otocinclus will be perfectly content in a 10-gallon tank.

What kills algae but won't hurt fish? ›

Step 3: Use hydrogen peroxide (H2O2) to help clear pond water: Another thing that works great for algae control in fish ponds is hydrogen peroxide (and no, it won't kill your fish!).

What kills algae permanently? ›

Bleach is great for killing algae (and other organisms that may lurk in your tanks) and for keeping it from coming back. Scientific research shows that using bleach that is made from a solution with 5.25% hypochlorite. Never mix bleach and chlorine together.

What kills algae without harming fish? ›

One of the best algaecides out there that is safe for fish is a peroxyhydrate granular algaecide (which comes under many brand names). This comes in a solid granule form, and when added to pond water, it oxidizes, which destroys algae growth!

Do you need an algae eater in a freshwater tank? ›

Do You Need an Algae Eater? There are many ways to control algae in the tank, and you do not necessarily need an algae eater to combat the problem. Because an algae eater means one more fish or creature in the tank, its needs have to be considered as well, and it may be best to control the algae in other ways, such as…

Do algae eaters keep tank clean? ›

There are a few different algae eaters to choose from including snails, shrimps and certain algae-consuming fish. They are cheap, they can help to increase the diversification of wildlife in your tank, and they keep your tank clean.

What algae eater eats the most algae? ›

Nerite snails (Neritidae family)

They are known to eat most species of algae and will even tackle the notorious hair algae. The nerite snail stays rather small (under an inch/2.5 cm) and can have very pretty shell colorations and patterns.

How often should algae eaters be fed? ›

Feeding Guide

Feed twice a day. To accommodate the slower feeding habits of most algae eaters, feed the amount of food your fish will consume within two hours.

Can I use no more algae with fish in tank? ›

This product must only be used at the recommended use rate of 1 tablet per 10 gallons (40 Liters) of aquarium water. Copper, one of the active ingredients in this product, is toxic to fish and aquatic invertebrates. If used at the recommended use rate, this product is not expected to be toxic to fish.

What is the minimum tank for a pleco? ›

If you plan on starting small, these fish do well in tanks that can hold up to 30 gallons when they're juveniles. Author Note: Tank size is where many beginning fishkeepers go wrong with the Common Pleco. Because these fish are usually sold as juveniles, some people think that they'll do fine with a smaller tank.

What is the smallest tank for a pleco? ›

Common plecos (Hypostomus plecostomus) need a minimum of 75 – 80 Gallons of the fish tank, while most dwarf plecos need at least 10 – 15 gallons of the water tank.

What is the minimum tank size for a small pleco? ›

The minimum tank size for a bristlenose pleco is 20 gallons. In this tank, you can house 1-2 adult fish. However, a minimum of 30 gallons is most suitable, and the bristlenose plecos will be healthier in a larger tank.

What fish can stay in a 2 gallon tank? ›

For these tank kits, the betta fish, small tetras, bloodfin tetras, small live bearers, cory catfish, white cloud mountain minnow, small barbs, and danois works well. The 2 and 2.5 gallon fish tank is not so small in size and they need proper illumination.


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