Top 5 Freshwater Aquarium Fish and Critters That Eat Algae

Eric is an aquarium enthusiast with over two decades of experience caring for a wide array of tropical fish.

Algae Eaters for Your Fish Tank

If your tank has become overgrown with algae, you might think that adding a few algae-eating fish or critters seems like a great idea. You’ll toss them in, they’ll spruce the place up, and all will be back to normal.

As it turns out, this is one of those good news/bad news situations. The good news is there are, indeed, several species of fish and invertebrates that will eat up the algae in your tank. Even healthy tanks have some algae growth, and these guys can help you keep things spiffy.

Now for the bad news: if algae growth is way out of control in your aquarium, no fish or critter can clean up the tank all by themselves. You are going to have to pitch in. Aquariums don’t become infested with algae because they lack algae-eating inhabitants. Major algae issues are often the result of poor tank management.

This isn’t as horrible as it sounds, and we’ve all been there. The first step in cleaning up your tank is figuring out why you have an algae problem to begin with. Often, all it takes is a few simple changes to your maintenance routine to reverse the process of excess growth.

Once you are on the way to solving that issue, or if you already know your tank is in good shape but you’ve got a little algae growth anyway, you can consider adding some of the fish and critters mentioned in this article to your stock.

Always make sure you thoroughly research any animal you intend to add to your fish tank. Think about their overall needs, whether they are a good fit for the tank itself, and whether they will get along with the aquarium inhabitants already in residence.

1. Plecostomus

The plecostomus is one of the best-known fish in the aquarium world, especially among those who have never owned a fish tank. This is probably because of the way it grips the sides of the tank with its mouth, scraping up any algae it can find, and making a downright spectacle of itself. Many people simply refer to plecos as suckerfish.

Plecos are voracious consumers of algae, and a great choice if you have a big enough tank. However, the common pleco can grow to a foot and a half in length. That means it is not a good option for any tank but the largest tanks. I would not keep a common pleco in a tank under 75 gallons.

Luckily, there are smaller species that may be appropriate. Rubber-lip and bristlenose plecos only grow to about seven inches as adults. Neither is a good fish for a 10-gallon tank, but you may consider them for a 30-gallon and up.

A few more considerations when it comes to the plecostomus: whatever species you choose, make sure you supplement its diet with algae wafers and include a piece of driftwood in the tank for rasping. Failure to meet their needs can lead to occasional aggression, so beware.

Also, be aware that plecos can demolish live plants as they are scanning them for algae, so if you have a planted tank you might want to consider a different fish.

2. Otocinclus Catfish

If your tank is too small for a pleco, or you don’t want to deal with the hassle of it rampaging through your live plants, consider the little otocinclus catfish instead. These guys only grow to a couple of inches, and they resemble tiny little plecos stuck to the sides of your tank. They are schooling fish, so you’d need a minimum of six to keep them happy and healthy.

You’ll see otos scrubbing the glass for algae, but they also have a tendency to disappear into the background. They are a great choice for any tank ten gallons and up, as long as it doesn’t include fish that are big enough to eat them. Be sure to include algae wafers so they are getting enough to eat, along with plenty of vegetation and hiding spots so they feel secure.

Otos are probably my favorite algae-eating fish, just because they are so easy to manage. However, I’ve also found that they can struggle when tank conditions are less than ideal. For this reason, I’d recommend having your water parameters well under control before adding otos to your tank. They are the ideal choice for many small tanks where a pleco is simply not a possibility.

3. Siamese Algae Eater

The Siamese algae eater is another fish known for its big appetite for algae. They’ll consume leftover fish food and plant matter too, which makes them one of the best clean-up fish you can have in your tank. They are generally docile, but they do grow to an adult length of around six inches, and so would not be a suitable choice for small tanks.

Take care to research and understand their needs before purchase. Be especially careful not to confuse the Siamese algae eater with the Chinese algae eater. And, be sure wherever you are buying your fish from knows the difference as well. Misidentifications can and do happen.

Chinese algae eaters grow larger and become aggressive fish as they age. I’ve had them before, and would not recommend them for a community tank.

As for the Siamese algae eater, a tranquil, planted aquarium with no aggressive tankmates is the best setting. While mostly docile, be aware that they may become territorial with other SAEs around. I would consider a tank 30 gallons or larger for a single fish, or 55 gallons and up if you have more than one.

4. Amano Shrimp

Amano shrimp, also known as algae-eating shrimp, are cool little crustaceans that will scavenge just about anything they can find in your tank. As their pseudonym suggests, they are particularly known for their big appetite for algae.

Ghost shrimp and cherry shrimp more common and less expensive options if you like the idea of shrimp in your tank. They will eat some algae, but just as importantly they’ll help take care of some of the problems that caused your algae bloom, such as uneaten fish food and decaying plant matter.

Shrimp are hardy and very easy to care for. Just drop them in and let them do their thing. They are also really fun to watch. You’ll see them puttering around the substrate, climbing plants and occasionally even swimming.

If you intend to stock any of these guys just be sure you are not serving them up as lunch. Larger fish will readily see them as food, so choose them for aquariums with small, community tankmates.

5. Mystery and Apple Snails

If you have an algae problem in your tank, you may have noticed a corresponding outbreak in pest snails such as pond snails, ramshorns, and Malaysian trumpet snails. Dealing with the algae issue can often reduce or eliminate your snail problem as well.

You’re not going to add pest snails to your tank intentionally, I hope. However, you may consider apple or mystery snails. They make for an entertaining addition to an aquarium and a cool alternative to another fish.

There are a few things you need to know before you include one of these critters in your tank:

  • While a snail will munch up algae like a champ, it might also munch up your live plants.
  • Some species can get fairly large. Research before you buy!
  • If you have more than one you may get baby snails.
  • Be careful when treating fish for illness if you have snails in your tank. Some medication that is helpful to fish can be harmful to snails.
  • Large, aggressive fish may pick on snails. While the shell offers some protection, it’s still not an ideal situation.

Guppies, Mollies, Platies, and Swordtails

These livebearers get an honorable mention. You may not think of them when trying to figure out a solution to your algae problem, but mollies, platies, guppies, and swordtails will all readily graze on algae. You’ll notice them picking it off decorations and even the gravel. They’ll also swoop in and munch on algae wafers.

I would never suggest relying on livebearers to handle the clean-up duties in your tank. Algae isn’t a main food source for these fish, and they still need regular fish food in their diets. But, it’s nice to know they are willing to pitch in and do their part in keeping the tank clean.

Additional Considerations

I have always fed algae wafers several times per week whenever I have algae eaters in my tank. I think it is a smart practice, as it ensures they will have enough to eat. Some aquarium owners will supplement veggies to make sure herbivores in the tank are getting the nutrition they need.

Be careful with medications when you have invertebrates in the tank. Some of them can be harmful to snails and shrimp. Do your research!

As I stated in the beginning, algae eaters will not solve growth issues in a poorly maintained tank. In fact, they could make things worse by adding to the bioload. But, they can help a lot in a healthy tank with a little excess algae growth.

Make sure you thoroughly research the animals you intend to add to your tank. Consider their needs, plus how they will interact with any other fish you already own. Think of the long view when choosing any fish or critter for your aquarium.

Remember, you don’t just want to solve a problem in the short term, but create a healthy miniature ecosystem that will thrive for years to come.

Eric Dockett (author) from USA on September 04, 2020:

@Janet - You have more experience than I do, it sounds like! So, if you aren't seeing signs of disease, the first thing that comes to mind is something called "old tank syndrome". This is where conditions slowly erode, and fish adapt for a while, then it reaches a tippying point and you'll have a die off.

You said water parameters are okay - did you measure nitrate and pH specifically? Sometimes this creeps up over time.

I am surprised you didn't see fluctuations in water parameters when you left the tank empty for a month. That kind of reductions in bioload should have made a big impact.

In any event, something is up and all I can do is guess without knowing more about the tank. But I would start with considering if your water is really okay or if there might be something going on that you missed. You asked this question in an article about algae. Are you having an algae issue? That too indicates that things may be a little off.

Maybe add fish slowly and alter some of your maintenance practices so you can be sure water quality is stable and safe.

Good luck!

janet on September 03, 2020:

Hello, I have kept tropical fish for over 45 years with success and am suddenly experiencing fish dying on mass. I spoke to an expert who advised about chemical levels in the water and bacteria but all these were okay and monitored routinely. They tank was left empty of fish for a month while all was rechecked. I restocked and three weeks later it is happening again. All water readings are well within parameters. What is happening. I am getting frustrated now.

3 Best Algae Eaters for Freshwater Aquariums

The following 3 Best Algae Eaters for Freshwater Aquariums

1. Otocinclus

Actually this one fish get into the cathfish species and is one of Algae eaters are quite effective. The advantages of this are the Otocinclus of small size that is only about 2 inches and they live on the surface of the aquarium (Aquarium base) so that they can be used in almost all types tanks.

Other articles you can read here.

The advantages of both of these fish that is Otocinclus not aggressive inside the tanks so you’ll very enjoyed it when looking at this one fish coexist with other fish in the Aquarium.

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Food favorites from Otocinclus this is brown algae (diatoms) that usually appears in an Aquascape during initial setup. They also usually will eat all types of soft algae include Green Dust Algae. Otocinclus have only one demerit i.e. fish meal this could be a bigger fish in the Aquarium especially if you keep the Cichilds species.

2. Caridina Japonica (Amano Shrimp)

Amano shrimp was first introduced by Aquarist Takashi Amano in the popular Nature style of the Aquascape. This shrimp is Algae eaters are reliable enough to kill the algae do not usually eaten by other species of Algae eaters. Amano shrimp usually eat Green Hair Algae and other green algae or can even clean up the feed is left inside the Aquarium.

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Only one downside of this type of shrimp, that is quite difficult to breed in fresh water and most have to breed in salt water, but they were pretty safe upkeep along with other fish in the Aquarium because of its size. Amano shrimp are rarely preyed upon by other fish unless you keep the big fish like Gurame in tanks.

3. Crossocheilus siamensis (Siamese Algae Eater or SAE)

Siamese Algae Eaters are quite frequently used as fish Algae eaters, but behind it all there is still a lot of shortcomings in these fish, these fish are only consuming the black and red algae.

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Moreover, sometimes they are also interested in consuming plants including harigrass, moss, and mayaca. Their appetite will decrease drastically after they lay eggs and will be very aggressive when their age already quite old with body length reaches 4 to 5 inches.

In order to keep the ecosystem inside your fish tank happy and healthy, you need to create a balance. If your aquarium is covered with lots of algae, then some hungry helpers can keep things under control.

Always ensure that the species you are placing in the tank are safe for your aquatic plants and can work together for increased effectiveness.

The good news is that there are literally hundreds of species of algae eaters for both freshwater and saltwater tanks that can help keep your tank’s ecosystem well-balanced.

I've been keeping fish for over 30 years and currently have 4 different aquariums – it's an addiction. I'm here to teach you everything there is to know about fishkeeping.

I also use this site as an excuse to spend lots of money on testing and reviewing different aquarium products! You can find my reviews here.

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Welcome to FishLab

Hi, my names Ian. I have been keeping fish for over 30 years. I can’t wait to teach you about the hobby!

When it comes to maintaining a thriving freshwater aquarium, there are many simple things you can do. One thing you should do is test your tank water weekly to make sure that your water chemistry remains stable. Installing a high-quality filtration system and performing routine water changes are important as well. In addition to these things, you might also think about adding some freshwater invertebrates to your tank to create a “cleanup crew.”

What is a Cleanup Crew?

A cleanup crew is simply an assembly of organisms that help to control the accumulation of detritus in your tank. Detritus is simply another word for the waste products that build up in the substrate of your tank. This includes uneaten fish food, fish feces, and decaying plant matter. A cleanup crew can be composed of various fish and invertebrates that are scavengers, naturally feeding on detritus. Snails are an excellent example of a scavenger that can be used in a cleanup crew – various species of shrimp and crabs also make good additions to the freshwater cleanup crew.

Best Freshwater Invertebrates

There are many different options to choose from when it comes to freshwater invertebrates, but some of them are better than others. Here are our picks for the top five invertebrates to consider for your freshwater cleanup crew.

  1. Nerite Snails: While some aquarium snails can become a nuisance, nerite snails are highly beneficial. These snails feed on algae and detritus but they tend to leave aquarium plants alone. Another benefit of nerite snails is that they cannot breed in freshwater so you don’t have to worry about them taking over your tank like some snails do. Plus, taking care of these snails is easy, so they are a great place to start when you are thinking about adding some invertebrates to your tank to help you keep things as clean as possible. Their lifespan ranges from 1 to 2 years, and they can reach up to an inch in size when they are fully grown. You should have a minimum of a 5 gallon tank if you are going to add nerite snails to your little ecosystem, though. And these freshwater snails like having driftwood and rocks in their environment as well.
  2. Amano Shrimp: These freshwater shrimp grow up to 2 inches long and they are known for eating all kinds of algae. Amano shrimp are generally peaceful so they won’t bother your other tank inhabitants, and they may even feed on leftover fish food and other detritus. One thing to be wary of, however, is that large fish might eat these shrimp so keep them with smaller, peaceful species. Once you get to know these cute little shrimp, which can live anywhere from 2 to 3 years, you won’t find it surprising when you learn that they are one of the most popular types of shrimp among aquarium hobbyists. They follow an omnivorous diet, and they require a minimum of a 10 gallon tank—preferably one that has plenty of live plants. Plus, these little guys will get along well with snails, other shrimp, and fish, so with the right combination of animals, you can easily set up a peaceful little community of varied species.

  1. Crayfish: Similar in appearance to small lobsters, crayfish can be a colorful and useful addition to the freshwater cleanup crew. Crayfish are scavengers that are likely to eat various types of detritus in the aquarium but they can be territorial with their own species so it is best to keep just one. If you’re thinking about adding crayfish to your tank, it’s important to know that you will need to set up your aquarium so that it will closely resemble the natural habitat of the crayfish otherwise, they can become stressed out, stop eating, and experience anxiety. Thankfully, it isn’t hard to get the job done, as you can simply line the bottom of the tank with rocks that they can hide in, along sand that they can burrow into. Your filter, water pump, or air pump should be able to mimic the current of a river. And, because these interesting creatures will eat plants, as well as algae, it’s best to add live plants that are fast growing to your tank. Beyond that, providing your crayfish with the appropriate pellet food will also keep them happy and healthy.
  2. Fiddler Crab: The fiddler crab is a small, peaceful species of crab that generally grows no larger than two inches. These crabs will eat almost anything, though they do require some salt in the tank water in order to survive. These invertebrates are ideal for brackish tanks. They can live anywhere from 2 to 3 years, and they need to live in a tank that is at least 10 gallons in size. The tank also needs to be set up with shallow water, and there should be areas of the environment that rise above the surface of the water as well—these crabs are semi-terrestrial, so they will need to be able to come out of the water as they please. In terms of setting up your aquarium as a community, working with an expert who really knows these animals is recommended. You’ll need to have fish that are not only able to live in a brackish tank, but who can also swim fast enough to get away from a crab that might be aiming to attack. Otherwise, you can maintain a tank that solely houses fiddler crabs.
  3. Freshwater Clam: These invertebrates act as living filters – they help to keep tank water clean by consuming detritus directly from the water column. Freshwater clams only grow about two inches long and they are fairly easy to care for as long as you don’t keep them with fish species that tend to feed on invertebrates (this includes pufferfish). They can also get along well with a variety of snails and shrimp, so you can have an entire cleaning crew to help keep your tank clean. Just bear in mind that they do prefer a pH of 7.0-8.0 or slightly lower, and a water temperature of 70-80°F, if not slightly cooler than that.

Keeping your freshwater aquarium clean can be a challenge since you have to maintain a balance between keeping your water quality high while also making sure your beneficial bacteria have the nutrients they need to thrive. Establishing a cleanup crew made up of freshwater invertebrates is a great way to improve the cleanliness of your tank without adding to your work load.

Watch the video: Top 5 BEST Fish Tank Cleaners! (July 2021).