Keeping an aquarium is a popular hobby around the world. It’s easy to keep an aquarium as what hobbyists do most times is feed their fish or other inhabitants. But maintaining a clean and healthy aquarium is challenging as algae can quickly become problematic.

Unlike other seaweeds, algae are one of the toughest to eliminate due to how they propagate. The good news is that algae growing in your tank doesn’t necessarily mean something bad.

Since algae is a natural part of the aquatic ecosystem, you can make the most of it when it grows in your tank. However, because algae can be beneficial, it’s no excuse to allow it to outgrow your tank, as it can make it challenging to maintain a healthy and stable environment in your tank.

In a situation where algae is growing in your tank, you can introduce small algae-eating fish. These fish snack on the algae, which fills their stomach, provides them with specific nutrients and helps you keep your algae issue under check.

This guide will review some of the top small algae eating fish you can consider introducing to your tank to keep it clean.

Top 8 Small Algae-Eating Fish

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Fortunately, you can choose from various small algae eating fish species to help eliminate algae in your tank. These fish are not only helpful in eating away the algae, but they are fascinating to watch and add to the overall aesthetics of your tank. From our research, below are our best small algae eating fish so far.

1. Chinese Algae Eater

The Chinese Algae Eater is among the most popular algae eaters. It particularly enjoys feasting on green algae. It’s a small, tropical freshwater fish that can grow up to 11 inches long, making it a sizable addition to your tank.

These Chinese Algae Eaters require a minimum aquarium capacity of 55 gallons. Also, they function best in temperatures ranging from 75° F to 80° F and pH readings of 6.5 to 7.5. Feeding the Chinese Algae Eater with algae at a tender age is fine, but they reportedly eat fewer algae as they mature.

As a juvenile, the Chinese Algae Eater is relatively peaceful but becomes more aggressive and territorial as they age. Unlike some small fish, the Chinese Algae Eater is worthwhile as it can survive in a tank with other large and aggressive inhabitants. For example, adding the Chinese Algae Eater to your tank is ideal if you have a cichlid setup infested with algae.


Note that the Chinese Algae Eater is not a part of the catfish family despite their resemblance. Instead, this fish has a long, slender body with a sucker-like mouth and small fins. It is quite a spectacular fish to watch, even though it is not the most colorful and striking algae-eating fish.

The Chinese Algae Eater has an average life span of ten years. Although its lifespan can be shortened or extended depending on the quality of care it receives. Note that the fish is quite agile and may try to jump outside the tank, so ensure the tank has a  lid with a latch to ensure their safety.

2. Siamese Algae Eater

Next on our list of small algae eaters to consider is the Siamese Algae Eater. This fish is a little hungry fish with an affectionate likeness for nibbling on algae. The Siamese Algae Eater is an effective option to keep your tank clean, as it will eat virtually every variety of algae in your tank.

The Siamese Algae Eater is a tropical freshwater fish requiring simple to medium care. It is an omnivore fish meaning it can eat a variety of diets. Also, the Siamese is not a picky fish that can scavenge dead insects, dead fish, plant matter, and other things.

The Siamese Algae Eater is a bottom-loving fish that can grow up to 6 inches or slightly longer. Most Siamese are slender and have a brownish-beige color. It also has a bold black stripe that runs its entire length. At first glance, the Siamese Algae Eater Fish looks like the Siamese Flying Fox Fish.

Both fish belong to the same family but have different genera and species groups. So, despite their resemblance, you will find several differences. One distinct feature is that the Siamese Flying Fox Fish has a golden band along the top border of its black stripe sides.

Another distinguishing feature is that the Siamese Flying Fox has an orange-yellow tinge on its fines, which is clear on the Siamese Algae Eater. Caring for the Siamese Algae Eater is easy, but ensure you keep the water condition optimal as its pH level must be 6.5 to 7.0, the temperature at 75° F to 79° F, and water hardness at 5 to 20 dH.

3. Otocinclus Catfish

The Otocinclus catfish is a peaceful tropical freshwater fish you can use to reduce algae growth in your tank. This fish is herbivorous, making caring for it quite technical. But as a herbivore, they perform excellently at reducing algae growth. An average Otocinclus Catfish is small, measuring 1 to 2 inches.

Another distinctive feature of the Otocinclus Catfish is its cylindrical body with short fins. Unlike other catfish, the Otocinclus Catfish has a row of armor plating across their body which helps protect it from other fish and rough surfaces.

Various Otocinclus Catfish come in different colors such as gold, orange zebra pattern, speckled brown upper body, mottled grey or brown coloring, and so on. Despite their size, the Otocinclus Catfish is ideal for managing algae in medium to large tanks.

Sometimes, these incredible small fish are called the Dwarf Sucker because they are small and use their mouth to latch onto things. In their natural habitat, these fish are often latched onto rocks, driftwood, or other stable surfaces to feed off algae.

The Otocinclus Catfish is a native South American fish often found in shallow streams and rivers. Also, the fish is quite nervous, which explains why it prefers to live in a vegetated area apart from its feeding habit. The Otocinclus Catfish has an average life expectancy of 3 to 5 years under ideal living conditions.

4. Twig Catfish

The Twig Catfish, also known as Farlowella catfish, is another common algae eater you can introduce to your tank. This fish is a freshwater fish with a special charm to it. There are well over 35 species of Twig Catfish, but two common ones seen in aquariums are the Farlowella acus and the Farlowella vittata.

The Twig Catfish is native to South America, with high density in Venezuela and Columbia. This fish prefers to live in areas with many plants as it offers them a place to hide and attach themselves using their sucker mouths. Twig Catfish also loves to nibble on biofilm and wood.

The Twig Catfish’s laid-back lifestyle contributes to its average lifespan of 10 to 12 years. These fish are small as juveniles but can grow as long as 6 inches. As such, the Twig Catfish requires an average large tank. We recommend using the Twig Catfish in a minimum tank size of around 35 to 40 gallons.

The water condition must also have a temperature ranging from 73° to 79° F and a pH of 6.5 to 7.5. Also, the water must have a hardness somewhere between soft and hard.

The temperament of the Twig Catfish is quite mellow and peaceful, and they love to scavenge for food on various surfaces. Also, the Twig Catfish spooks easily. So, if you are going to keep the Twig Catfish with other tank mates, ensure it’s one that’s very mellow and nonaggressive, like Cory Catfish, Green Neon Tetras, and so on.

5. Koi

Koi, or the Japanese Koi, is another brilliant algae eater popular for its colorful form. There are several varieties of Koi with different patterns. The most popular varieties of Koi are the Showa, Sanke, and Kohaku. Generally, Koi are small fish that take a while to grow but can grow up to 3 feet.

Koi have a rich history in Asian culture dating back thousands of years. Most people keep Koi as ornamental fish in outdoor ponds or garden water features.

But aside from the aesthetic appeal of Koi, they help control algae growth. Koi are omnivores, so they eat both plant and animal-based diets. And it doesn’t matter what level the food is, be it at the bottom or mid-level, Koi feed at all levels.

If you introduce Koi in your pond, it’s best to provide a suitable environment. Koi are temperate fish that can adapt to temperatures between 45 and 95 F.

Koi fish are one of the longest-living freshwater fish. In ideal conditions, Koi can live up to 25-50 years. There are even records of Koi living up to 100 to 200 years. The oldest Koi ever documented lived up to 226 years.

6. Cory Catfish

Cory Catfish, also known as Cory Cats or Corydoras Catfish, are freshwater fish. This fish is described as armored catfish because of their plate of bone-like material that runs the entire length of its body. The Cory Catfish are peaceful bottom scavengers making them a go-to choice for anyone looking for tank cleaner.

Introducing the Cory Catfish to your tank will help feast on algae and uneaten food that sinks to the bottom, thus keeping your tank clean. The Cory Catfish are small fish ranging from 1 to 2.5 inches. As a small fish, the Cory Catfish can survive in small tanks measuring 10 gallons and above.

The Cory Catfish are easy to care for as they perform well in various water conditions. Ideally, the pH of the water should be between 7.0 and 7.8 and temperature between 72 and 78 F. Also, the lighting should be kept relatively standard and not too bright, as Koi are timid fish.

Koi are also very social and are often happier in a group of two or more. So, if your aquarium size permits, aim to include six or more Koi simultaneously.

Cory Catfish are long-lived fish with an average lifespan of 5 years or more under the right conditions. So, ensure all toxic matters such as nitrate and ammonia are kept at 0 ppm. Also, although Cory eats algae, ensure you feed them regularly.

7. Bristlenose Plecostomus

The Bristlenose Plecostomus fish, sometimes called the Bushy Nose Pleco, is another common algae eater aquarists often use. Pleco is a freshwater fish that belongs to the Loricariidae family. It’s a perfect fish to introduce to your tank if you’re still a novice aquarist, as they are easy to care for.

Originally, Pleco comes from streams in the Amazon Basin. But today, they can be seen in other areas like Central and South America. The Pleco are small fishes; an average Pleco can measure up to 5 inches long.

Pleco has a wide range of food in its natural habitat. Since Pleco often spend their time in shallow streams, they feed on algae and other plant-based diets. Sometimes they can cling to plants to eat insect larvae.

Including the Pleco in your tank ensures the water condition is suitable. The water temperature must be between 60° and 80° F, the pH range between 6.5 and 7.5, and the water hardness must be between 6 and 10 KH. Adult Pleco can handle slight fluctuations in water conditions, but it’s best to keep it constant.

Note that there are several varieties of Pleco, like the Albino Bristlenose Pleco, the Longfin Bristlenose Pleco, Super Red Bristlenose Pleco, and so on.

8. Hillstream Loaches

Finally, Hillstream Loaches are also excellent algae eaters to consider including in your tank. It’s a freshwater fish with a unique body shape and pattern. These fish don’t only look neat but are easy to care for. Loaches are omnivores, so they can eat animal and plant-based diets, especially algae. You can find them scavenging and looking for anything to nibble on in the wild.

The Hillstream Loaches look like a mini-stingray or a catfish but are neither. These fish have a busy pattern covering their body, including their fins, making them unique. The pattern can be light greyish-yellow or black strips that go randomly all over their body. Their pectoral and pelvic fins look like wings which they use to move and secure themselves to rocks and other surfaces.

The Hillstream Loaches are small fishes measuring anywhere from 2 to 3 inches long. As such, you can easily introduce them to small tanks of about 50 gallons or more.

The tank must be in perfect condition, which you can use a testing kit to monitor as loaches thrive in water with temperatures between 68° and 75° F and pH levels between 6.5 and 7.5. Also, the water hardness ought to be medium.

Loaches are social fish, so they are best kept in a group and do well with a tank mate. So, if the size permits, it’s best to introduce at least 3 or 4 into your planted tank.


In summary, if algae growing in your tank can have many disadvantages, like disfiguring your tank’s aesthetics and competing with other vegetation for nutrients, you can turn the situation around by adding an algae-eating fish.

These fish nibble on the algae in your tank, which helps keep the tank clean and provides them with nutrients. Although don’t make the mistake of relying on feeding your algae; eat fish with only algae. You will still need to provide it with other essential nutrients to thrive.

Also, be cautious when adding another inhabitant to your tank, as some aquatic animals don’t coexist well. So, ensure you consider everything when making a choice.

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