Algae Eating Pond Fish post

If you are reading this article, it’s safe to assume that you have an algae problem. You built a beautiful pond water feature in your backyard. Did the research, and installed a properly sized UV light. But there is one thing missing. String algae is everywhere and adding one or more species of these algae eating pond fish to your pond will definitely help.

As you know it is an ongoing struggle to battle with the notorious green stuff all season. Get rid of some of that algae and have well fed fish at the same time... it's a win win. Let's take a look at some helpful pond fish that feast on algae. In the video below I take a trip to the local aquatic pet store searching for algae eating fish to add to the pond.

Here is our list of fish that will help to clear the water in the most natural way possible. They are organized on the chart below with additional information on each species below that. If you are planning on adding any of these species to your pond, there are links below some of them to be ordered online from Amazon. 

*** Use the name in the chart below for quick navigation to more information on that species.


Min Pond Size

Min Water Temp

Average size in inches

Winter In Pond



14" inches



48" inches



48" inches



14.5" inches



36" inches



12" inches



24" inches



2" inches



2" inches



4" - 6" inches



4" - 6" inches



2" inches

Algae Eating Pond Fish For Small Ponds

Otocinclus Catfish (Otocinclus vestitus)

If you go down to your local pet store that has any variety of fish, you are sure to come across an Otocinclus Catfish. You may even mistake it for a common pleco. They look similar having the same type of specialized mouth to scour the bottom eating algae as it goes.

A tiny cousin to the common pleco, it is well suited for smaller ponds. With an average size of only 2 inches, it can get algae in hard to reach places that other types of algae eaters may have left behind.

Otocinclus Catfish

They do best in shallower water, and because of their tiny size will not disturb other plants in the pond. Perfect to keep a deck or patio water garden free from algae.

Siamese Algae Eater - (Crossocheilus oblongus)

Well I guess the name says it all. Although not a large fish, topping out at a maximum of 6 inches, for its size has a ferocious appetite for algae. These fish are best suited for smaller ponds. 

siamese algae eater

The Siamese algae eater is in the carp family, similar to koi and goldfish, originating from Southeast Asia, and is suited for warmer climates. They will not survive in waters that dip below 70℉. This algae eating pond fish will need to be removed and brought indoors once the water temperature drops. 

Distinguished by their black stripe that runs down their side. A peaceful fish that is a welcome member to any pond or aquarium. For smaller ponds it is recommended to add more than one to keep the algae at bay. These fish are not aggressive and school well together. 

Flying Fox (Epalzeorhynchos kalopterus)

The flying fox is sometimes mistaken for the siamese algae eater. They share similar characteristics. Both species are from Southeast Asia making them suited only for warmer waters. 

flying fox

The Flying Fox is known to eat algae, although they are small in size. The average size (wikipedia site) of a flying fox is around 4.7inches. The small size makes them suitable for smaller ponds and water gardens and should be removed or brought indoors once the temperature drops below 70℉.

When kept in a small water garden on a deck or patio, they can simply be brought in for the cooler weather.

Mollies (Poecilia sphenops) & Guppies (Poecilia reticulata)

I group these together because of their similar size and effect on algae control. Both of these are small in size, but what they lack in size they make up in numbers. Placing a group of either of these in your small pond may not make a huge impact at first, but once they begin to procreate, (and they do at a phenomenal rate) they will make a significant difference on the algae growth. 

black mollies
orange molly

The only problem with both these fish is they are very sensitive to cooler water temperatures. Guppies will do well as long as the water is above 55℉ where as mollies hate cooler water. They will not do well in water temps below 75℉. Keep this in mind if you plan on using these in your backyard patio water garden. Bring them indoors when the temperature drops.

Goldfish (Carassius auratus)

The goldfish is one of the hardiest species to inhabit backyard ponds and watergardens. Although we have it listed here as a fish for small ponds, goldfish will thrive in any size environment. In aquariums they have stunted growth, but in a pond environment will grow up to 12” - 14”.

There are three main types of goldfish that you will find in ponds, all with similar algae eating attributes.



Sarasa Comets​

When it comes to eating algae any of these three will do its fair share. When left unfed by humans they will do a better job of clearing up algae. One of my clients has a small pond with a handful of small comets. The pond is only 18inches deep. These goldfish are not fed and keep the water from being overrun by algae growth. 

shubunkin goldfish

The goldfish would not be able to keep up with the amount of algae from a larger pond, they would need some help from other species on our list. 

Algea Eating Pond Fish For Meduim To Large Ponds

Common Pleco (Hypostomus plecostomus)

You have probably seen one of these if you have ever been to a pet store that has fish. You see one of these in just about every tank. That's because they are great at removing algae. The common pleco aka sucker mouth catfish has a specialized mouth that allows it to scour the bottom and devour algae. 

pleco mouth up close

This algae eating fish will do well in it’s own 1000 gallon area. We don’t recommend adding more than one pleco to your pond unless it has enough room. There are many variations of the pleco pictured below are just a few.

gold spotted pleco

Spotted Pleco

albino brustlenose pleco

Albino Brustlenose Pleco

rhino pleco mouth up close side view

Rhino Pleco

The pleco will get along with koi and pond goldfish like comets, sarsas, and shubunkin's, however may “butt heads” and be aggressive toward smaller fish. Be aware that a pleco will reach 24” or more in the right environment.

Once the water temperature begins to dip below 50 it’s time to move your pleco indoors. This species of fish originates from South America and will not survive the freezing temperatures of winter in a pond.

Koi (Cyprinus carpio)

Although koi considered algae eating pond fish, they will hardly make a dent in an overgrown pond. Algae can take over quickly and your koi will not be able to keep up. Especially since they are probably spoiled eating the high protein food you feed them. These fish eat algae like most people take their salad… on the side. 

submersible light on koi fish

Koi (link to our article all about koi) will eat some algae but not wipe it out completely by any means. This is good news because there will be enough left over for a true algae eater like other fish that made this list.

Koi (link to our article all about koi) will eat some algae but not wipe it out completely by any means. This is good news because there will be enough left over for a true algae eater like other fish that made this list.

Pond Loach (Misgurnus anguillicaudatus)

pond loach

The pond loach loves to play hide and seek. After adding this peculiar creature to your pond, you may think it had disappeared. Its size and color make it easily blend in. The pond loach does well in cooler water, although it will not survive a harsh winter. Once the water temperature drops below 40℉ it’s time to bring indoors out of the weather.

Not only does this pond fish eat algae, but insects and other vegetation are all part of its diet. Because of Its varied diet, the pond loach will not eat as much algae as some other species on this list.

Pond loaches do well in small groups, and are not aggressive. Growing up to 12 inches in a pond environment, a pond loach makes an interesting addition to any water feature.

Large Pond Algae Eating Fish

Mozambique Tilapia (Oreochromis mossambicus)

According to Pond King,  Mozambique Tilapia are the go-to fish for getting rid of algae in large ponds. He recommends adding 10lbs per acre. The fish will begin chowing down on the algae as soon as they are acclimated to their new environment, usually a few days to a week.

Mozambique Tilapia out of water
Mozambique Tilapia

Most large pond owners will start to notice a change to their pond within a few weeks. What really sets the “clean up” in motion is when the water reaches the optimal temperature for spawning. Once this happens, there are tons more mouths to feed, resulting in even more cleanup.

Mozambique Tilapia have a biological control built in. They will not survive in cooler waters. To help your pond look its best, stock these in the spring and let them take care of the algae all summer long. Once the temperature drops, their metabolism slows down making them easy to harvest. When introduced to your pond they return to their wild state.Mozambique Tilapia make a great game fish, and when left to their own taste much different than their farm raised counterpart

Batfish (Myxocyprinus asiaticus)

The Batfish also known as the Chinese High-Fin Banded shark is a catfish with an appetite for algae. This algae eating fish has similar traits to the common pleco and Otocinclus Catfish. The batfish grows at a slow rate, however its overall size can reach over 48 inches in length when fed well. Recommended for large ponds, this beast will help keep any algae problem at bay.

high fin banded shark (batfish)

This is one of the few on our algae eating pond fish list that can survive a cold winter. Just like koi and goldfish, the batfish will survive sub zero temperatures as long as there is a hole in the ice (link to winterizing your pond article) to prevent poisonous gasses from building up.

Grass Carp (Ctenopharyngodon idella) 

If you plan on stocking your large pond with these algae eating gluttons, the fish you get from the hatchery are treated. By treating these fish to give them three sets of genes instead of two, they are rendered sterile. This ensures that this invasive species will not take over your pond or any other water way for that matter.

grass carp

Grass carp, as their name implies have a primary diet of musk grass, duckweed and algae. This algae eater typically weighs in at around 55 pounds. Steve Pollick of outdoor news tells of an instance where he added a grass carp to his large overgrown pond and in a couple of years was left with a barren “aquatic desert”.

Algae Eating Pond Fish For Cold Climates

I have scoured the internet looking for anyone that has any recommendations for algae eating fish that can survive cold winter. The closest thing I found was a forum where someone had kept a Pleco in their pond in New York. 

***Note... this information was found on a forum and I don’t recommend doing this. He claimed the pleco had survived three winters, and had adapted quite nicely to the cold environment. We recommend adding a pleco to your pond, but remove it when the water temperature drops below 50. 

Just be aware that Plecos will grow up to 24” in length especially in a pond environment. Keep that in mind when planning to bring them indoors for the cold season.

This is what you are faced with if you live in a cooler climate like the Northern United States. The options are limited to goldfish for small to medium ponds. Koi for medium to large ponds and the Chinese High-Fin Banded shark (Batfish) will help you gain control of algae blooms in large ponds.

These three algae eating species will survive the winter. Without having to remove them at the end of the season, they provide a low maintenance solution for your water feature.


Most of these fish will serve you well if you live in a climate that rarely dips below 40℉. So what do you do if you live in a cooler climate that experiences winter? You have a couple choices. You can either add the above mentioned fish to your pond, or add the fair weather fish for the season and remove them to an indoor aquarium for the winter. 

Understand that adding algae eating pond fish to your pond will not completely eliminate algae. These fish eat algae to survive. When a sudden algae bloom occurs in the mid summer heat, these fish may not be able to completely keep it at bay.

Using other methods to deal with your string algae problem such as installing a UV light and adding barley straw are two great ways to help reduce algae. Also having enough plants in your pond will help starve algae. The ion gen system (link to our review of this system) is another alternative method to eliminating algae.

The best way to keep your pond looking its best and keeping the water clear and free from algae blooms is by doing a combination of all of these methods. If you install a UV light, keep your pond well planted and add some species of algae eating pond fish you will be on your way to a crystal clear clean pond all season long. Until next time, enjoy your backyard water garden.


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About the author


I love being outdoors and hands on DIY. If you share my passion, you are in the right place. If I can help one person surprise themselves with the success of a project, then this website is a success.

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