Turn your algae problem into a feast for your fish. The fish that eat algae and will make your tank look amazing.

Algae play an important role in freshwater environments like ponds and aquariums by providing food and oxygen for fish and supporting the overall ecosystem balance. 

Sometimes it create problems for fish health and environment of the water.

But don’t worry, Algae-eating fish will solve your problem.

Fish that eat algae will keep the Algae problem in control.

Fish That Eat Algae

Here is a chart summarizing some of the main types of algae eating fish and their efficacy at consuming different kinds of aquatic algae:

Fish Species	Green Spot Algae	Hair Algae	Brown Diatoms	Green Water Algae	Overall Algae Grazing Ability
Plecostomus	High	Moderate	High	Low	High
Siamese Algae Eater	Moderate	High	Moderate	Low	High
Otocinclus Catfish	Moderate	Low	High	Low	Moderate
Bristlenose Pleco	High	Moderate	High	Low	High
American Flagfish	Low	High	Low	Low	Moderate
Hillstream Loach	Moderate	Low	High	Low	Moderate
Amano Shrimp	Moderate	High	Moderate	Low	High
Nerite Snail	High	Moderate	High	Low	High
Koi Fish	Low	Low	Low	Moderate	Low
Goldfish	Low	Low	Low	Moderate	Low
Molly Fish	Low	Low	Low	Low	Low

This chart summarizes the ability of some popular algae eating fish and invertebrates to consume common algae types found in freshwater aquariums, such as green spot, hair, diatoms and floating algae. It also shows their overall efficacy as algae grazing species.

Plecostomus (Common Pleco) Algae Eaters

This suckermouth catfish is probably the most popular algae eating fish used in home aquariums. They use their large sucker mouth to attach themselves to surfaces and rasp algae off with their teeth. They get quite large though (over 1 foot).

Plecostomus are a type of armored catfish native to freshwater habitats in Central and South America.

They have heavy armored plates on their bodies and wide, flat heads with a ventral suckermouth surrounded by fleshy lips.

Common Plecos can grow over 12-15 inches in the wild and live 10+ years. Different Plecostomus species span a wide range of sizes though.

Pleccos use their strong suckermouths to securely latch onto hard surfaces like driftwood, rocks and glass.

Their lips conceal teeth that can efficiently rasp soft algae off surfaces, removing green spot algae, brown diatoms and green filamentous algae.

They locomote along surfaces using their suckermouths to access and clean algae in hard-to-reach spots.

Provide sinking algae wafers to supplement natural grazing and plenty of rock and driftwood surfaces for adhesion.

Give them cave-like hiding spaces and low water flow since they originate from slower moving streams and rivers.

Common Plecos produce a substantial bioload from their waste due to large mature sizes. Good filtration is a must.

Siamese Algae Eater 

The Siamese Algae Eater is another popular fish used to help control nuisance algae growth in freshwater aquariums. 

The Siamese Algae Eater (SAE) comes from flowing rivers in Thailand and other parts of Southeast Asia.

They have an elongated, torpedo-shaped body with a horizontal black stripe behind the dorsal fin running from head to tail. Males also develop a golden-orange colored lateral line when mature.

SAEs reach up to 6 inches in length when fully grown.

In the wild, SAEs scrape diatoms and brush algae off of submerged roots, rocks and bogwood using specialized teeth in their mouths.

They voraciously seek out and feed on black beard algae and hair-like filamentous algae in the aquarium which few other algae eaters consume.

For sufficient nutrition, they still need plant-based foods like veggie flakes, algae wafers or blanched zucchini to supplement their grazing.

SAEs are very active swimmers requiring ample open space in planted aquariums to utilize their full range of movement.

They school together in groups of 5-6 fish which exhibits natural behavior and reduces aggression. Having fewer can make them territorial.

The Siamese Algae Eater uses its activity level and resilient teeth to keep troublesome brush algae under control in the aquarium while remaining a reasonable small size.

Otocinclus Catfish

The Otocinclus is a lesser-known but highly efficient algae eating fish perfectly suited for most home aquariums due to its small size and peaceable temperament.

Otocinclus catfish originate from gently flowing freshwater rivers and streams across north and central South America.

They have oval shaped bodies rarely exceeding 2 inches in length. Their mouths form a ventral suction cup with scraping teeth underneath.

Columnar in shape, Otocinclus swim and rest in an upright vertical posture aided by specialized fins.

For their small stature, Otocinclus have formidable appetites for both diatoms and green spot algae coating leaves and hardscape.

Using coordinated flashes of activity, groups of 4-6 readily clean algae invested surfaces and plant leaves that larger fish cannot access.

Unlike plecostomus, their tiny size and lower bioload makes them suitable fish algae eaters for nano and small planted aquariums.

The small profile, energetic feeding behavior and hardy constitution of Otocinclus make them one of the most proficient algae eaters available for planted aquariums both large and small. They are perfect “clean up crew members.

Koi Fish

Koi fish will opportunistically feed on algae, but they are not considered dedicated algae eaters compared to fish like Plecostomus and Otocinclus catfish which rely predominantly on biofilms and algal growth for sustenance.

Koi fish are a domesticated color variant of the common carp from Asia that have been selectively bred for their vibrant orange, white, yellow and black patterning.

They possess ventral sucker-like mouths with pharyngeal teeth adapted primarily for feeding on benthic organisms, plant material and debris along pond bottoms rather than scraping algae adhered to surfaces.

Though not their primary feeding preference, Koi will ingest strands of filamentous green algae and some large-celled phytoplankton to supplement their diet, particularly as juveniles.

However, their impact on attached forms of algae like diatoms and thick coatings of green spot algae is minimal compared to algal grazing specialists.

A nutritionally balanced Koi diet consists mainly of plant matter, insects, insect larvae as well as Sinki pellets formulated for Koi to maintain rapid growth rates and brilliant coloration. Algae alone cannot satisfy their dietary needs.

For hobbyists seeking fish that make a visible dent in nuisance algae growth, true algae eating fish should be paired with Koi rather than relying solely on supplemental Koi grazing which is inconsistent and modest at best in terms of algae control.

Goldfish Eat Algae

Goldfish will eat some algae incidentally as they forage, their role in supervised algae control is negligible. Instead, best practice pairs true algae-grazing fish like nerite snails or Siamese algae eaters with goldfish.

Goldfish (Carassius auratus) are a popular freshwater fish kept as pets in home aquariums and ponds but they are not specialized algae eaters by nature compared to some other fish.

In the wild, goldfish feed on a variety of foodstuffs including plants, insects, crustaceans, and detritus. They will occasionally pick some algae off of surfaces but they do not actively graze on algal growth like plecostomus catfish or Otocinclus do.

Goldfish may ingest filamentous floating algae and loose algal debris when foraging at the bottom or mouth-picking in the water column but they do not utilize algae as a consistent or necessary part of their diet for nutritional purposes.

Chinese Siamese Algae Eater

The Chinese Algae Eater (also called Chinese Siamese Algae Eater) is often confused with the true Siamese Algae Eater. 

Native to inland rivers in East Asia, mainly China and Taiwan.

Resembles the Siamese Algae Eater as a juvenile but has a thicker body, no black stripe, and grows much larger.

Can reach over 16 inches (40cm) long as an adult.

As a juvenile, this fish eagerly consumes hair algae, green spot algae and brown diatoms

Its algae grazing enthusiasm decreases dramatically as it matures.

Adults are extremely territorial and aggressive, not compatible with community tanks. Despite its name, the Chinese Algae Eater is NOT an effective long-term algae management solution.

Initially eager algae munchers, Chinese Algae Eaters ultimately stop feeding on algae once mature. Their aggressive nature also makes them incompatible tank mates. True Siamese Algae Eaters or Otocinclus catfish make for more suitable and peaceable algae eating fish.

Bristlenose Pleco

The Bristlenose Pleco is a smaller species of algae-eating suckermouth catfish well-suited to planted aquariums for its petite size and relentless appetite for both floating and attached algal growth.

The Bristlenose Pleco (Ancistrus sp.) comes from oxygen-rich rivers in South America, primarily within the Amazon river basin.

They possess armored plates across their bodies and a ventral suction pad mouth for adhering to surfaces. Short tentacle-like bristles project from heads of mature males.

Growing to only 3-5 inches on average, the Bristlenose remains a manageable size for most home aquariums compared to the Common Pleco which can exceed 12 inches.

Using their suckermouth, Bristlenose Plecos efficiently get rid of all types of algaes including green spot, black beard and brown diatoms.

Their small size enables them to clean algae in hard-to-reach spots on leaves and in rock crevices larger plecos cannot access.

Groups of 3-4 readily clarify aquarium glass and decor of unsightly algal growth.

A proven workhorse for controlling various types of algaes, the eager Bristlenose Pleco is perfectly suited to planted aquariums and nano tanks given its modest adult dimensions and hunger for both floating and attached algal growth.

American Flagfish

The American Flagfish is a strikingly patterned native North American fish increasingly valued for its voracious appetite for hair algae and suitability for specialized planted aquarium setups.

The American Flagfish (Jordanella floridae) comes from slow-moving waters across Florida and areas of the central United States.

They exhibit a unique red, white and blue color pattern on their fins reminiscent of the American flag which gave rise to their patriotic name.

Flagfish reach approximately 3 inches in length when fully grown.

Flagfish aggressively consume troublesome black beard and hair-like varieties of algae that thrive in high-tech planted tanks.

Using quick movements, they clean broad-leaf plants, decor and glass surfaces by grazing on algal coatings.

They are proficient at clearing outbreaks of black brush algae and staghorn algae.

Reticulated Hillstream Loach

The Reticulated Hillstream Loach is a unique species of algae grazing fish perfect for planted aquariums needing extra surface area cleansing power.

The Reticulated Hillstream Loach comes from rapidly flowing streams within Southeast Asia’s rainforest ecosystems.

They have flattened ventral sucker mouths surrounded by sensitive tactile lips used to graze algae coating riverbed stones.

Their laterally flattened bodies and specially adapted pelvic fins allow them to adhere to surfaces in fast current.

Using their suckermouth, Hillstream loaches efficiently graze soft green spot algae and brown diatoms off smooth leaves.

They thrive in high oxygen ripariums and paludariums with emergent rock work to mimic their natural habitat.

Occasionally they will pick at soft floating algae within the water column as well.

The unique adaptations and grazing behavior of the surface-clinging Reticulated Hillstream Loach allow them to reach and devour algae inaccessible to most other aquarium fish, making them a specialized algae control addition.

Amano Shrimp

While not a fish, the Amano Shrimp has rightfully earned its place as one of the most efficient algae eating species available for planted freshwater aquariums.

Amano Shrimp (Caridina multidentata) come from temperate freshwater streams in Japan and neighboring Asian countries.

Growing up to 2 inches long, they have translucent bodies with red dashes along their sides and gray-green dots blending into planted tank backgrounds.

Peacefully industrious, groups of Amanos diligently pick hair algae, green dust algae and brown diatoms from plant leaves other algae eaters miss.

Using their fan-like pleopods and mouthparts, they efficiently clean broad leaf surfaces and tank decor.

They will also pick at leftover fish food and fish waste among plant thickets.

Bristlenose Catfish

Bristlenose catfish are a group of small, suckermouth armored catfish valued for their algae grazing services and suitability for home aquariums.

Using sucking mouths, bristlenose catfish graze all types of algae including green spot algae, brown diatoms and soft filaments.

Small size allows them to clean algae in hard-to-reach spots like on plant leaves and decor crevices.

Considered excellent “clean-up” crew members for most home aquariums.

The bristlenose catfish group contains several of the most popular and capable algae managing species available to freshwater aquarists, controlling “problem” algae growth on decor, glass and plant leaves.

Nerite Snails

Nerite snails have earned their place along with fish as effective algae eaters for home aquariums.

Small freshwater snails named for the glossy nerite patterns on their spiral shells. Popular varieties include horned nerite, zebra nerite, black racer nerite.

Native to brackish coastal tidal marshes and swamps, Nerites graze smoothly across aquarium glass, leaves, decor consuming most algae forms.

Particularly effective on green spot algae and brown diatom algae, also feed on soft film algae and detritus containing vegetable matter.

Groups of nerites thoroughly clean tanks of unsightly algae other species cannot tackle

Do not harm most plants or living tissues while rasping algae. 

Whiptail Catfish Eating Algae

Whiptail catfish possess several natural adaptations allowing them to capitalize on eating algae, keeping their surrounding aquatic environments clean.

Originating in rivers and streams of Central America and South America. These have long slender bodies with striped patterns along lateral lines. Use extended sensory barbels on heads to detect food, Flattened, sucker-like ventral mouths allow them to attach to surfaces.

Modified mouths allow them to scrape and rasp different types of algae off rocks or glass. Feed extensively on diatoms and green varieties of algae coating underwater surfaces.

These are capable of reaching difficult areas, cleaning algae off stagnant tank walls, decor. Also feed opportunistically on insect larvae and vegetation.

Whiptail catfish have developed specific physical and behavioral feeding methods for accessing and ingesting nutritious and abundant algal films. Their incorporation enhances overall aquarium cleaning duties and ecological balance.

Twig Catfish

The Twig Catfish is an efficient algae eater that utilizes some clever adaptations to help clean aquarium tanks.

This slender brown catfish has a flattened ventral mouth surrounded by suction lips, enabling it to scrape and suck soft green algae and brown diatoms off leaves and glass. Its tiny flattened body shape lets it wedge between narrow crevices and clean recessed areas that are difficult to access. 

It also has sensitive tactile barbels to detect nutritious algal coatings on surfaces to graze on. 

Often it will hang vertically on the glass under dim lighting to feed on green spot algae accumulations. The Twig Catfish tends to favor softer greens and browns over tougher hair or black beard algae.

In addition, the Twig Catfish is a very peaceful nocturnal bottom dweller that spends its days hiding amidst plants. Despite rarely being seen, it helps immensely to clarify plant leaves of debris and reduce algae accumulations on glass and rocks overnight. 

While it does not directly consume fish waste, its grazing habits help process some excess nutrients that could fuel heavier algae growth.

Rubber Lipped Pleco

The Rubber Lip Pleco is a member of the suckermouth armored catfish group with some unique advantages for algae control. Found in fast-flowing rivers of South America, especially the Amazon basin, their mouths contain rubbery lips and papillae used to scrape algae off surfaces. 

These catfish have grayish-brown bodies with pale undersides and yellow seam fins. They grow to about 6 inches in length.

The Rubber Lip Pleco uses strong suction power to latch its ventral mouth onto tank walls or decor. It then utilizes its rubbery lips to efficiently scrape green spot algae and brown diatoms off hardscapes. Its modified intestine allows it to digest plant matter like fibrous algae.

For algae control, the Rubber Lip Pleco has tireless appetites for hair algae, soft film algae, and stubborn green spot algae on aquarium glass. Its smaller size compared to common plecos allows it to clean tight spaces and underneath leaf undersides. Its peaceful nature also permits grouping multiple Rubber Lip Plecos together to maximize algae grazing impact.

With a tenacious ability to attach to then rasp algae from smooth surfaces using its unique mouth and lips, the Rubber Lip Pleco makes an excellent cleaner organism for controlling unsightly buildup of green and brown algae in home aquariums.

Benefits of Algae Eater Fish

Keeping dedicated algae eater fish provides multiple benefits for home aquariums and aquatic environments.

Algae Control – Algae eaters like plecos, otocinclus catfish, and Siamese algae eaters graze on problematic algae such as green spot algae, efficiently cleaning decor, tank walls and plant leaves.

Nutrient Exportation – By ingesting and assimilating algae, algae eating fish effectively remove excess nutrients like phosphates and nitrates fueling algal growth. This improves overall water quality.

Oxygenation – Algae perform photosynthesis, releasing oxygen into aquatic environments. Sustaining algae populations through controlled grazing helps maintain oxygen levels.

Food Web Support – Algae form the base of aquatic food chains. Algae eaters support overall ecosystem diversity by facilitating algae growth and recycling nutrients back into the system.

Natural Appeal – Watching specialized algae consumers actively tend to aquarium surfaces offers insight into natural grazing behaviors and ecological balance that is aesthetically pleasing.

Algae eating fish like bristlenose plecos and Siamese algae eaters enhance aesthetics, sustainability and biodiversity by controlling algae proliferation, filtering water, and serving vital ecological roles. Their incorporation leads to healthier, more stable aquariums.

Can Any Fish Eat Algae?

While some fish species like Plecostomus and Otocinclus specialize in eating algae, most fish do consume some algae or algae based material as part of their diets:

Herbivorous fish that normally feed on plant matter routinely ingest algae like soft green filamentous algae as supplemental nutrition. Examples are Goldfish, Cichlids, and Guppies.

Omnivorous fish often browse and pick at algae growing on surfaces or floating in the water column while foraging for insects and invertebrates. Species like Barbs, Tetras, and Rainbowfish fit this group.

Even primarily carnivorous fish like Bettas, Tiger Barbs, and Gouramis may bite at hair algae or green spot algae adhering to leaves and tank walls out of curiosity and changing tastes.

During the juvenile developmental stage of their lives when protein demands are lower, fish across most feeding groups tend to sample more algae to complete balanced diets.

Summary : Fish That Eat Algae In Tank and Ponds – What Fish Eat Algae

Algae-eating fish comprise a diverse group of species spanning different families of fish with specialized physical and behavioral feeding adaptations allowing them to consume the various forms of nuisance algae that commonly grow in home aquariums.

Fish such as the Plecostomus, Siamese Algae Eater, Otocinclus catfish, and Bristlenose Pleco are some of the most popular algal grazing species valued for their unique sucking mouths for attaching to and efficiently scraping soft green hair algae, spot algae and stubborn brown diatoms off tank walls, decorations, and plant leaves. 

Species of similar size can be grouped together to enhance overall algae removal from an aquarium’s submerged surfaces.

While fish such as Goldfish and Mollies contribute only minor incidental algae grazing, dedicated algae consumers like the Nerite snail and Amano Shrimp often pick up the slack, cleaning remaining troublesome varieties like black brush algae from crevices fish cannot reach. 

Different grazing species also facilitate algae control at different tank levels from substrate surfaces to upper water vegetation.

The presence of efficient algae-feeding fish and invertebrates improves aesthetics via clearer viewing, enhances water quality by exportation of excess dissolved organics, and helps recreate balanced low-maintenance ecosystems. 

Hobbyists should research the specific types of algae different algal grazers consume when compiling the optimal “clean-up crew” for their planted aquarium system. Managing the algal bloom problem with nature’s own methods leads to sustainable and healthy freshwater habitats.