Last Updated on January 1, 2020 by Aiden Lindow

10+ Ultimate Algae Eating Fish

algae eating fish

Algae is something no one wants in their pond, and without the proper care, it is a reality for most pond owners. By putting in a small selection of algae-eating fish into a pond, you can easily remove almost all the growing algae.

Algae is going to show up in any pond no matter what. It comes from any plants containing chlorophyll-a and spreads at a very rapid rate. 

Algae live and grow in stagnant water and can quickly fill an entire pond if the conditions are right and nothing is done to prevent it.


How Does Algae Grow?

Algae likes to grow in small ponds for a number of reasons. When the pond is exposed to a lot of daylight, or there are high levels of nitrate within the water, protoctist (Algae) can and will grow.

Hot and wet weather will stimulate inaugurate algae growth, particularly once the water if stagnant and does not have a filter.

If there are any decaying leaves within the pool, or if there’s an absence of aquatic plants, protoctists will thrive furthermore. 

A technique to prevent the rapid growth of algae is to introducing algae-eating pond fish into your water garden.

The presence of algae in your pond isn’t always a bad thing.

In fact, when properly controlled, having some green algae (not the blue-green algae) in your garden pond is actually considered healthy and necessary.

It helps the aquatic ecosystems as they will produce oxygen and provide a natural food source for many fish, insects and wildlife species.

However, if allowed to grow out of control, algae can kill everything in your pond as it uses up all of the nutrients and dissolved oxygen content.

Utilizing various pond fish, like the ones discussed below, is an environmentally friendly and simple way to ensure that algae populations are kept at a balanced and sustainable level.

Although no pond fish will likely be able to fully control a rapid algae bloom (more on this later), they’re a great natural method for reducing its growth alongside more traditional means.

How Does Algae Grow?


What Fish Can Help In Cleaning A Pond?

Before we get to the best algae eating fish, it should be noted that when feeding your fish, make sure that you are not feeding them any more than they can eat within a five-minute span.

Any uneaten food will add nutrients to the water and further encouraging algal growth.

Plus, fewer supplemental feedings for your fish means that they are more likely to feed on algae that are present.

Making use of an automatic feeder can be helpful in these situations to carefully monitor dosage and frequency. 

While fish feeders are not super cheap, I recommend getting one as they make it very easy for when I leave town or to feed my fish the right amount of food.

The feeder I use is the Fish Mates Fish Feeder and it has to be my favorite. Check Price Here

Certain species of fish can help in cleaning a lake by consumption of protoctist (algae), collections of inexperienced organisms that seem like plants, but not eating any actual plants. 

 I have written a full guide on how much and when to feed your fish to prevent algae here.

Best Algae Eating Fish

When selecting algae eating fish, remember how big your pond is and how many fish you will need to clean it.  You might only need two plecos, or you might need ten loaches and ten mosquito fish.


  1. Common Pleco

 The common Pleco is also called the suckermouth catfish. The common pleco (Hypostomus plecostomus) is all-devouring, fish that will eat any plant material it can find. It also eats small insects that may have fallen in the pond.

It can grow to more than 24 inches long and is known for being aggressive in adulthood, so stick to one or two plecos in your pond at a time.

Common pleco


  1. Mosquito Fish

Mosquitofish (Gambusia affinis) are tiny minnows that mostly feed on algae and mosquito larvae. 

Mosquitofish are compatible with most ornamental pond fish, but they live most harmoniously with fish their own size, as larger fish sometimes eat mosquitofish.

If mosquito fish live with larger fish, provide them with plenty of hiding places such as rocks and vegetation.

Mosquito fish


  1. Siamese Algae Eater

The Siamese algae eater (Gyrinocheilus aymonieri) could be a massive lake fish native to Asia. It grows up to 11 inches long and uses its sucker-like mouth to remove algae attached to rocks, plants, and sides of the pond.

The Siamese Algae Eater is often territorial, therefore make sure it does not attack other fish in your pond. 

Siamese algae eater


  1. Grass Carp

Grass carp (Ctenopharyngodon idella) are voracious feeders and if it is available, eat 40-300%  of their weight daily in the material.

They eat algae, however, are often selective eaters and like nonmoving vegetation like grass on the bottom of ponds.

However, grass carp are smart decisions for semi-permanent management of non-moving vegetation.

Grass carp


  1. Pond Loach (Misgurnus anguillicaudatus)

If you’d rather not worry about having to transfer your algae-eater inside for the winter, a pond loach (also known as the dojo loach or weather loach) may be more suited to you.

They’re quite hardy fish, able to live in waters ranging from about 40 to 77°F, and are well-suited for beginner ponders.

They can grow up to a foot in length and prefer to live in small groups, although they should be fine in a community of other species so long as they’re docile.

Loaches don’t consume as much algae as certain species such as plecos because they are opportunistic feeders that will also eat insects, plant matter, and food pellets.

However, they’re one of the few algae eaters that can not only live in but prefer cooler water. This makes them a great choice for pond owners with cooler weather throughout the entire year.

If you have really cold winters, it’s still best to bring them indoors if possible or install a pond heater to keep them comfortable.

Pond loach


  1. Koi & Goldfish (Cyprinidae)

Being two of the most commonly kept pond species, you’ll be happy to hear that both koi and goldfish are omnivores and will indeed feed on algae to some extent.

However, algae is certainly not their preferred food source and generally feed more heavily on algae only during the winter when they are dormant and there are fewer food options available.

In warmer months, both fish species will prefer to eat their regular feed and various pond insects that happen to end up in your water garden.

Having more goldfish or koi in your pond will help ensure that more algae gets eaten, but you may want to also incorporate other algae-eaters if they are not doing the job.

Plecos generally do just fine with koi, but can inadvertently latch onto smaller goldfish and damage their scales and necessary slime coating if there isn’t much swimming space in your pond.

If you’re worried about the potential problems of adding more fish species, we recommend using other methods of algae control as both goldfish and koi really do prefer other types of grub!

koi and goldfish


  1. Mollies & Guppies (Poeciliidae)

If your pond doesn’t have a significant algae issue and you’re looking for smaller, attractive fish, mollies and guppies are a good choice.

Like koi and goldfish, algae is not their main diet but they will eat soft green algae off of your pond liner, rocks, plants, and other substrates.

In addition, they’re both considered easy species to take care of and will reproduce fairly quickly, meaning that these little guys can put a surprising dent in overall algae growth.

If you wind up with too many of them, most pet stores and aquariums are willing to buy mollies and guppies.

They will need to be brought inside for the winter, as mollies prefer water above 75°F and guppies do best in temperatures over 55°.

If you have a very small water garden, they’re probably one of the most effective and cheapest fish species for controlling algae, they also help keep mosquito larvae and other insects at bay!

In larger ponds, they’re less useful as they’ll be readily eaten by larger fish and likely won’t be able to keep up with the algae spread.


  1. Otocinclus Catfish (Otocinclus arnoldi)

Many fish keepers and small-scale pool house owners take into account this small catfish to be one in all the most effective algae-eaters out there!

Although they are very small in stature, at only 1 to 2 inches long, they are ravenous when it comes to algae, and will happily eat the slimy brown algae and any newly growing algae as soon as it appears.

Because of their small size and calm nature, they do well in groups with most other fish species and will not damage other fish as they feed (as mentioned above, this can be a problem with larger suckering algae eaters).

They’re also gentle feeders, meaning that they can get to algae in hard to reach places without harming the plants in your pond, which may be useful if your pond has plenty of nooks and crannies.

algae eating fish

Otocinclus Catfish

Not really a good choice for large ponds with bigger species as they’ll get eaten pretty quickly and won’t make much impact on algae growth, but they’re a good choice in smaller water gardens.

Also, they’re best suited for tropical climates when it comes to outdoor stocking, as they require warm water temperatures, ideally within the 72-82°F (22-28°C) range.


  1. Chinese High-Fin Banded Shark (Myxocyprinus asiaticus)

A shark that eats algae? What? Actually, this fish (also known as the freshwater batfish) is more closely related to the suckering algae eaters talked about in this article than it is to actual sharks.

As a bottom feeder, algae make up the most significant portion of their diet. Batfish has a prominent, high dorsal fin that inspired its name, and bold banded coloring that makes it quite eye-catching.

Despite their ability to grow up to 4 feet long (don’t worry, they’re slow growers), they’re a peaceful species that easily live in harmony with koi, goldfish, guppies, and many other fish species.  

These fish prefer to live in small schools of 3 or more of their own kind.

algae eating fish

Chinese High-Fin Banded Shark

In addition, they’re quite hardy and prefer cool water with plenty of hiding places, though anywhere between 55-75°F suits them just fine.

Since they’re a very large species, you’ll need a decently sized pond to accommodate their growth, so this choice is only really suitable for very large (and deep) pond designs.


Are Pond Fish Enough to Control All Algae?

Sadly, in almost all cases, algae in ponds will eventually begin to grow faster than fish can actively consume it – especially in the summer months.

Pond fish may be able to graze down algae during quieter periods, but as soon as the sun begins to shine during the summer months, algae will start to win the battle and gain a foot-hold over the ecosystem.

In situations where you’re suffering intense algae growth, the only realistic way to control it would be through more traditional methods designed to target specific algae types and remove them quickly before they can re-grow.

These methods include UV clarifiers, pond vacuums, barley straw, and even natural algae deterrents, such as pond plants. 

All of these methods are safe to use with fish, so combining them alongside your natural algae eaters will ensure you keep the maximum amount of algae growth controlled.

More information on these methods can be found in our separate articles below:


If you have got a large lake or a major quantity of algae growth, additional voracious, larger algae eating fish just like the pleco, Siamese algae eater, or Chinese high-banded shark could also be higher fitted to your lake.

If you have got a smaller lake or don’t have a considerable quantity of algae, additional general species like koi, goldfish, mollies, and guppies can possibly work simply fine for keeping your lake system well-balanced.

If your region experiences temperature fluctuations, semi-cold-tolerant species embrace acanthopterygian, the lake guppies, koi, and a few cyprinid fish species.

Once selecting associate degree algae eater, you’ll additionally have to be compelled to be conscious of the fish already gift in your lake – acanthopterygian and otocinclus catfish square measure friendly with alternative fish.

However, Siamese algae eaters could also be too energetic and stress out any calmer fish gift, whereas koi might eat smaller fish.