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What is an Algae Eater?

Posted by on Feb 09 2024

For many fishkeepers, algae growth in an aquarium can be a recurring problem. Additives and treatments can help to get rid of aquarium algae but algae eaters play a crucial role in maintaining the delicate balance of aquarium ecosystems. These aquatic clean-up crews are valued for their ability to control and consume algae growth, which can contribute to a healthier and more visually appealing aquatic environment. But what is an algae eater and what do you need to know before introducing one to your aquarium? Let’s dive into the subject.

What Are Algae Eaters?

An algae eater is an aquatic organism known for its capacity to consume and control algae growth within aquariums. These valuable creatures help prevent the overgrowth of algae, promoting a balanced and healthy ecosystem. 

Do Fish Eat Algae?

Yes, many fish species are natural algae eaters and consume various types of algae as part of their diet. Although algae-eating fish are known for their ability to help control and manage algae growth in aquariums, you should always try to get the algae in the tank under control before introducing any algae-eating species. 

How To Spot An Algae Problem

Several signs indicate that you may have an algae problem in your aquarium. These signs include:

  • Excessive green water: If your aquarium water has turned green, it is likely due to an overgrowth of algae. This is particularly common with free-floating algae.

  • Algae on glass and decorations: Visible algae on the aquarium glass, decorations, or substrate is a clear sign of an algae issue.

  • Reduced water clarity: Algae blooms can lead to a decrease in water clarity, making the water appear cloudy or tinted.

  • Unpleasant odour: An unpleasant smell coming from the aquarium may indicate an excess of decaying algae.

  • Algae on plants: While some algae on plants is normal, an overabundance may indicate an imbalance in the aquarium environment.

  • High nutrient levels: Elevated levels of nutrients like nitrate and phosphate can contribute to algae growth. Regular water testing can help identify these issues.

  • Algae in filter: Algae growth within the filter media or other equipment is a sign that algae is growing in the aquarium.


How to Identify Algae

Identifying different types of algae in your aquarium requires a keen eye for colour, texture, and growth patterns.

Green algae, for instance, typically exhibit vibrant green hues and can take various forms, including hair-like strands or spot-like clusters.

Brown algae (diatoms) often create brown coatings on surfaces, resembling a thin film or dusting.


Red algae can range from red and purple to brownish or greenish colours, often presenting as branching structures or encrusting surfaces.


Observe where and how the algae grow, whether on glass, decorations, or plant leaves. Filamentous algae form long threads, while diatoms might create a powdery appearance. Regular and close observation will enhance your ability to promptly identify and manage specific algae types in your aquarium.


What Are the Best Algae Eaters for Aquariums?

Algae eaters come in various forms, but the most popular types for aquariums are fish and invertebrates such as shrimps and snails. Each species has unique characteristics that make them effective in controlling various types of algae, providing a natural and balanced solution for maintaining a healthy aquarium environment.

What Type of Fish Eat Algae?

Several fish species are renowned for their algae-eating capabilities. Siamese algae eaters and certain catfish species are popular choices for aquarium enthusiasts looking to control algae naturally. These fish not only contribute to the aesthetic appeal of the tank but also serve a functional purpose in algae management. The type of algae eater fish you get should largely depend on the type of algae growth you have in your tank, as some species have preferences when it comes to their taste in algae.


What Fish Eat Green Hair Algae?

Siamese Flying Fox 

These fish are also known as Siamese Algae Eaters (SAE) and for good reason. This species has a hearty appetite for hair algae, especially when they are juveniles. When they get older, they may eat hair algae at a slower rate. Siamese algae eaters can grow to around 15cm so they are better suited to a large aquarium with a community of larger fish species. As the SAE reaches maturity, they can become territorial so it's a good idea to keep one or keep them in groups of three or more where they can diffuse the aggression among themselves.


What Fish Eat Black Beard Algae?

Dwarf Suckermouth Catfish

Also referred to as Otocinclus Catfish, this species is one of the few fish that will eat black beard algae efficiently. Great for beginners, this hardy species is easy to care for and can be kept in a small aquarium since they only grow to 5 cm. Dwarf Suckers can eat black beard algae from the glass, rocks and plants thanks to their small mouths that get into small crevices and cracks between rocks and plants. These fish can be quite timid and may hide away if they are alone. Since they prefer to shoal, be sure to keep them in groups as this will make them feel more secure which will lead to them being more active and better at eating the black algae.


What Fish Eat Brown Algae?

Bristlenose Catfish

This breed of catfish, also called the Bristlenose Pleco is better suited to a larger tank since they can grow up 15cm long. This hardy species of Plecostomus is well-known for its brown algae-eating habits and will remove it from rocks, flat surfaces and large plant leaves. They may even start to nibble at your aquarium plants if there isn't too much algae in the tank so invest in some algae wafers to ensure they get enough to eat.


Do Snails Eat Algae in a Fish Tank?

Yes, many species of aquatic snails, such as Nerite snails, are known to eat algae in a fish tank. They graze on surfaces and are particularly good at getting rid of stubborn algae buildup on the glass with their teeth. Generally, nerite snails can't breed in freshwater, they will lay eggs but they need brackish water to hatch. This is good news as snails are notorious for overpopulating fish tanks, but with nerite snails, this won't be a problem.


Are Shrimp Good Algae Eaters?

Species like Amano shrimp and certain dwarf shrimp (such as Cherry shrimp), are good algae eaters and make a great addition to community aquariums. They actively graze on algae, helping to keep aquarium surfaces clean and fortunately don't add much waste to the tank. The popular Amano shrimp grow to around 5cm and it's recommended to get 3 to 4 as this will make the shy creature more outgoing and likely to venture out in search of algae. 

Cherry shrimp come in a multitude of colours and can't breed in freshwater so no risk of overpopulation. If you are getting shrimp, make sure to create somewhere for them to hide and moult safely. As they moult, their body is softer and more vulnerable to nibbles from other fish. While they may not consume large amounts like some fish or snails, shrimp are equipped with pinchers that allow them to get to the harder-to-reach areas.


What do Algae Eaters Eat When There is no Algae?

When there is no algae available, algae eaters still need a balanced diet to maintain their health. Many algae eaters are omnivores, and their diet can include specialised algae wafers ,  sinking pellets and even some fresh vegetables like blanched courgette or spinach. Some species, like Plecos, may also consume wood as part of their diet, and it's essential to provide a variety of foods to meet their nutritional requirements even when algae is scarce. Regular feeding with appropriate foods ensures that algae eaters receive the necessary nutrients for their well-being.


3 Things to Consider Before Getting Algae Eaters

When introducing algae eaters to aquariums, compatibility is a key consideration. Some species may coexist harmoniously, while others may exhibit territorial behaviour. Understanding the compatibility of different algae-eating species helps prevent conflicts and ensures a peaceful community within the aquarium.


Algae eaters contribute to preventing excessive algae growth, but effective aquarium maintenance practices are equally essential. Regular water changes, proper filtration, and proper feeding habits collectively contribute to a well-managed aquarium environment where algae eaters can thrive.


There are common misconceptions surrounding algae eaters, and people often make assumptions about their ability to eradicate all forms of algae. It's important to clarify that while they are great at controlling algae, a sensible approach to aquarium maintenance is necessary to address the root causes of algae growth.


Shop Our Algae Control Products

If you’re looking for additional supplies to help control algae in your aquarium, CD Aquatics stocks a range of aquarium supplies from algae magnet cleaners and nitrate removers to high-quality algae wafers and food for algae-eating fish. For more information about our algae control products, contact our team today or call us on 01922 416284.

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