6 Best Algae Eating Fish for Ponds (with Videos!)

Algae eating fish are one of Nualgi Ponds’ favorite and environmentally-friendly ways to control algae in your pond.

In this article, we’ll discuss our 6 favorite algae eaters for ponds and how to choose the best fish based on your pond’s size, water conditions, and cohabitants. Each fish description also has a video where you can watch them swim. Happy Ponding!

6 best algae eating fish for ponds - Header Image

Whether you want to add algae eating fish to help control pond algae or just want ideas for what fish you stock in your pond, this guide is for you!

Avoid stocking your pond with the wrong type of algae eating fish or you will end up with a pond full of algae and starving algae eaters!

Take your time and plan out your future fish. Adding more will increase the fish load and potentially decrease the dissolved oxygen available, leading to more algae. Balancing your ecosystem’s nitrogen cycle should be goal #1 when fighting to control pond algae.

What types of algae will fish eat?

In general, algae eating fish will feed on any green algae, including carpet algae and filamentous / hair / string algae, but will not feed on the planktonic algae that causes green water in new ponds OR the more toxic Cyanobacteria, more commonly referred to as blue-green algae.

How do I choose the right algae eater for my pond?

To determine if a given fish can survive and, hopefully, thrive in your pond, it’s necessary to consider a number of important facets of a pond’s ecosystem and its inhabitants.

Take an inventory of these factors in your pond to select the right algae eater from our list:


  • Water temperature: Start by thinking about your average year-round temperature. You’ll find some fish are better suited for a warmer climate and will not survive, while others will need extra care to survive a cold winter. If you live in a warmer region with temperatures above 70 F, some of our recommended algae eaters might not survive the negative effects of high temperatures on ponds.
  • Size & depth of pond: This is the next most important factor. Will your small pond be able to accommodate larger fish as they grow bigger? Half the algae eaters in our list require a minimum of 1,000 gallons to live and one of them can grow to 4’6”. Not sure pond size? Read these tips on how to measure the size your pond.
  • Other fish & cohabitants of pond: This is a very important question to ask. Do your current fish or critters mesh well with your chosen algae eater? Championship koi owners should think twice about adding any fish that may show aggression to a prized fish!
  • Ph level: What is the Ph of your pond’s water? Make sure you pick an algae eater that matches your existing conditions or your new fish may struggle.
  • What algae is in your pond: Consider what type of algae you are experiencing, how much there is to remove, and where that algae is most present, to help inform the best type of fish that will feast on algae in your pond.

What are the best algae eating pond fish?

Each of the following fish have descriptions on minimum pond size, average fish size, life expectancy, water conditions, pond type and other helpful information to help you choose which is best for your pond.

By using these algae eating fish along with other natural pond care practices (and a rake or shovel), you will be able to create a thriving pond ecosystem with long-term stability.

Koi (aka Nishikigoi)
Cyprinus carpio

Koi are our favorite algae eating fish but not the most voracious algae eaters

Min. Pond Size

Over 1,000 Gallons


Avg. Fish Size

12 to 15 inches

Avg. Life Expectancy

25 – 35 years

Generally the most popular fish to add to your pond, Koi come in over 100 different varieties, that can be breathtaking to look watch. A koi fish’s ability to help eat algae often is overlooked as a benefit.

Algae is not the favorite food of koi, but in the absence of other (tastier) food, koi will eat algae and plants as part of their diet; especially during winter months as food is more scarce.

How to get your koi to eat more algae

If you want to get your koi to help more, try developing a hand-feeding relationship with your koi, and then try hand-feeding them algae from your pond. It doesn’t always work, but we have seen some koi develop a taste for algae with this method.

There is a fish that snacks more heavily on algae though it may not be as social. What fish is that? The very next on our list.

Pond Size

A pond with at least 1,000 gallons is recommended. Plan for a larger pond than originally needed so you can expand.

Water Conditions

Koi prefer water temperatures between 61˚F – 72˚F (16.0˚C- 22.0˚C) with a pH level between 6.9 – 7.8.


Generally docile but may show signs of aggression during mating season.

Taro Kodama explains the beauty of his Kohaku Koi for sale from the Kodama family’s Hawaii Koi Farm.

Channel Catfish
Ictalurus punctatus

channel catfish eating algae in a pond

Min. Pond Size

Over 1,000 Gallons


Avg. Fish Size

15 to 24 inches

Avg. Life Expectancy

15-20 years

Channel Catfish are known for their catlike appearance due to whisker like tendrils. It is an amazing algae eater as an omnivore and scavenger. It is really quite the famous fish and are bottom feeders.. You’ve probably seen them during fishing trips and pond shop visits, especially true if living in North America, as they are in abundant supply within the region.

Their strong sense of smell makes them very good at eating various foods, including algae!

But, are Catfish aggressive?

Catfish can be aggressive. They may attack and eat other fish of their size or crustaceans, which can be dangerous depending on what fish already exist in your pond. However, they can also be good pond mates depending on environment and food available. Catfish will also snack heavily on different algae, but could also eat your expensive koi food and bully out your koi.

If you are looking for a fish that tends to be a bit more social, while also eating algae, our next fish may be for you!

Pond Description

A pond with at least 1,000 gallons is recommended. At least 8 ft deep with edges of pond sloping quickly to 3 ft deep, which reduce aquatic vegetation problems.

Water Conditions

Channel Catfish prefer water temperatures between 75.2°F-86°F (24oC–30 oC) with a pH level 5.5-7.5.


Channel Catfish can be aggressive toward other fish and eat a variety of both plant and animal matter.

Video of channel catfish swimming along the side of a small pond after being released into water.

Join Our Pond Care Tips Newsletter

Sign-up for our newsletter to get pond care articles & resources delivered right to your inbox!

Join Our Newsletter

Chinese High-Fin Banded Shark
Myxocyprinus asiaticus

Chinese high-fin banded shark eating algae in a pond

Min. Pond Size

Over 1,000 Gallons


Avg. Fish Size

Up to 39 inches

Avg. Life Expectancy

25 years

On top of it’s algae eating diet, it is cool to say that you own a shark! The Chinese Hi Fin Banded Shark is actually part of the Catostomidae family in a group of fish known as suckers.

These fish are not “suckers” when it comes to sucking up algae. Most of its diet can consistent of only natural algae! They tend to do well in groups, so you may wish to consider introducing a few at a time in the pond.

Growing to be about 4.5 ft, algae is its main diet and is a great addition to ponds for controlling algae growth.

With their trademark high fin reminiscent of a shark combined with their docile nature, they can be pretty fun to watch swimming through the pond.

Is it a friendly shark?

The Chinese Hi Fin Banded Shark is definitely a friendly fish and can socialize well with others. This is another big plus, as not all fish get along well with others, even though they may be great algae eaters.

What fish fits this description? The one just below.

Pond Description

Use a pond or water garden with 1000 gallons or more of well-filtered, moving, and well-oxygenated water.

Water Conditions

Temperatures between 61˚F – 72˚F (16.0˚C- 22.0˚C) with a pH level between 6.9 – 7.8 work well for this fish. Can tolerate temperatures as low as 40˚ Fahrenheit.


Peaceful/Docile. Offer krill, earthworms, and prepared fish foods like koi pellets to keep the bottom feeder coming to the top for meal time.

Jeff from Sunland Water Gardens showcases one of his favorite algae eaters for ponds.

PRO TIP: It is important to not overfeed. Reducing feed will force your fish to eat more algae, and more importantly, further prevent the growth of algae! Leftover uneaten food creates excess nutrients in the pond, which can fuel algae growth and be harmful to fish.

Flying Fox
Epalzeorhynchos kalopterus

Thai Flying-Fox Algae Eating fish

Min. Pond Size

Minimum 30 gallons


Avg. Fish Size

Up to 6 inches

Avg. Life Expectancy

8 to 10 years

The Flying Fox, originating from Southwest Asia, is notorious for eating green algae. You can find this small fish zipping to and fro, nibbling down on algae growing on rocks, plants, waterfalls, and elsewhere it can graze. This fish can stress other fish with its energy and may require more oxygen than others.

Pair a few of these algae eating fish with a beautiful water garden, and you’re on your way to giving algae the boot, the natural way!

Will Flying Fox eat my water plants?

Yes, some algae eaters will nibble down plants. Finding a balance between algae eating fish and pond plants that remove excess nutrients will help your pond glisten in natural clear beauty!

The Flying Fox appearance is quite nice, and actually somewhat similar to another great algae eater, the Pond Loach!

Pond Description

Minimum 20 gallons. Keep your Flying Fox in groups with larger numbers, to see how peaceful they can be. Plan for a larger pond to accommodate plants where it can rest and have multiple Flying Fox.

Water Conditions

Flying Fox prefer water temperatures between 75°F – 79°F, (24 – 26 C); with a pH level between 6.0-7.5


Typically docile, may become territorial at times. Well-manners with other species, but has been found to chase its own species.

Video shows tips for identifying Siamese Algae Eater and a Flying Fox in 4ft aquarium. 

Pond Loach
Misgurnus anguillicaudatus

Pond loach aka Weather loach (Misgurnus fossilis)

Min. Pond Size

Minimum 20 gallons


Avg. Fish Size

Up to 12 inches

Avg. Life Expectancy

7 to 10+ years

We mentioned Koi being one of our favorite fish and the importance of pairings when introducing different species of fish into a pond. You’ll find the Pond Loach can be a great match!

Besides being hungry algae eaters, Pond Loach get along very well with Koi and goldfish. They’re buds!

Its always good to quarantine new fish before introducing them to the main pond to be sure they are healthy and free of disease. These are very hardy fish and can live in poor water quality.

Having a couple Koi and Pond Loach could be a great way to combat algae in your pond. Beyond being bottom feeders, Pond Loach are known to snack on insects and small aquatic critters. If you’re facing mosquitoes, check out these helpful tips for overcoming mosquitoes in your pond.

Where is my Pond Loach hiding?

The loaches are active fish that will hide and explore. You may find that it will disappear after introduction to your pond and reappear later. They have a strong jumping ability, so add barriers and look in filters if your pond loach is not coming out to play.

Pond Description

At least 55 gallons and can live in poor quality pond water.

Water Conditions

Pond Loach prefer water temperatures between (68-72°F, 20-23°C) and can do well even at temperatures as low as the upper 50’s Fahrenheit (13-15° Celsius) with a pH level of 6.5-8.0.


Typically docile and hiding but can be active yet peaceful. May become territorial at times. Does great with koi and goldfish.

Large pond loach swimming around in outdoor UK pond.

Japanese Trapdoor Snail
Viviparus malleatus

Japanese Trapdoor Snail - Pond snail for eating algae

Min. Pond Size

Any sized ponds.


Avg. Snail Size

About 1 to 3 inches

Avg. Life Expectancy

1 to 5 years

Probably one of the most docile algae eaters on our list, is the Japanese Trapdoor Snail / Chinese Mystery Snail! Trapdoor snails can pick up loose food, as well as eat soft algae, for those times where we may have overfed our fish and have some leftovers on the pond floor.

They will also eat algae off stems of plants, but not the plant, making them a good fit for water gardens. Ensure there is enough naturally occurring soft algae for them to eat.

Remember, uneaten food converts to nitrogen which helps fuel algae growth so cleaning out the pond floor is key.

The dark-side of snails…

Snails can be a lot of fun to have, but be warned… they also can cause pollution to a pond in the form of waste, which may be worse than the algae they consume. For pond owners with a lot of Koi fish, other pairings may be a better fit.

Pond Description

They can be kept in small ponds and larger sizes but keep in mind they will add to tank waste so avoid overstocking. Japanese Trapdoor Snails are very active in low light settings.

Water Conditions

Japanese Trapdoor Snails are one of a few snail varieties that can over-winter well 7 survive in harsher northern climates. 64 to 84 °F (12.8-28.9 °C)


They only breed a few times a year and will not take over your pond how other nuisance egg bearing snails will.

Jeff from Sunland Water Gardens explains why snails are great when you have pond plants.

Will fish that eat algae be enough for crystal clear water?

The short answer is no. At Nualgi Ponds, we believe the secret to natural pond care is a strong Bio-filtration system that combines beneficial bacteria with oxygen producing pond plants and diatoms (the good algae!), which creates an efficient Nitrogen cycle for waste management in your pond.

To build a strong Nitrogen Cycle you need an active bacteria population and high levels of dissolved oxygen.

SUPERCHARGE your Nitrogen Cycle with the oxygen-producing power of diatoms!

Nualgi’s silica-based formula encourages new diatom growth within hours of using in your pond.

The diatoms photosynthesize and increase the amount of dissolved oxygen in your pond’s water column before being consumed by zooplankton, which are then consumed by fish in a happy little food chain!

Algae Eating Fish & Nualgi Ponds is a Great Combo!

Promotes fish health and controls nuisance algae Nualgi Ponds has been designed specifically to grow diatoms for improved water quality, clarity & stability.

We are proud that our customers find Nualgi to be the best solution for removing algae naturally, while also creating a environment for all inhabitants.

100% Safe for all Fish, Plants, Amphibians, Birds & Pets!


Try Nualgi in Your Pond!

We’d love your comments below!

Do you have any of the algae eating fish above? How much algae have they eaten? Would you recommend them to new pond owners? Do you see any fish we may have missed?

We’d love to hear your comments, feel free to share your pond management tips and suggestions below!


    Submit a Comment

    Your email address will not be published.

    Want to Receive Pond & Koi Care Tips?


    Sign up for our Newsletter to get first look at all of our pond care articles & resources for pond owners as well as exclusive discounts on Nualgi products.

    Want to Receive Pond & Koi Care Tips?

    Almost Finished! Please confirm your subscription by clicking the link in the email we just sent you.