What To Know Before Purchasing a Siamese Algae Eater

siamese algae eater

Many fish tank owners cry out in frustration around the world, for their arch-rival, a persistent and intrusive entity known as algae, keeps finding its way into the aquarium. No matter what you do to control algae, you might find that it will keep popping up on the walls, substrate, and even the plants in the tank. Sometimes, your lighting will even get dimmer because of algae.

It’s time to bring in the experts, the Navy Seals of the marine world.

We’re talking about Siamese algae eaters, a humble little fish with a major advantage over scum. As the name implies, Siamese algae eaters (SAE) consume algae happily. However, there are some things you need to know before you go out to purchase a Siamese algae eater or two for your aquarium.

About Siamese Algae Eaters

siamese algae eater
Care Level:
PH Level:
between 6.5 and 7.0
Water Temp:
around 75-79 degrees F (23-26 degrees C)
Min. Tank Size:
20 Gallon
10 Years
Color Form:Gold/Grey with Black Stripe
Tank Set-Up:Freshwater, Heavily Planted
Compatibility:Peaceful Community Fish

Originating from Southeast Asia, including places like Thailand, Singapore, and Malaysia, Siamese algae eaters are freshwater fish of the Cyprinidae family, making them relatives of carp. 

You can find SAE in many different environments, as well. Sometimes, you can come across schools of them in flood forests, feeding on the algae growing on submerged plant life or dwelling along the bottoms of rivers and streams throughout Southeast Asia.

Since they are considered one of the best algae eaters you can buy for your aquarium, these fish are now bred throughout the world. One of the reasons for their popularity is their high energy and efficiency. Even a single Siamese algae eater can clean a 10 gallon fish tank quickly when compared to more stationary scum suckers, like nerite snails.

Although these fish are called algae eaters, they are actually omnivorous. SAE will eat on zooplankton, phytoplankton, and algae.

algae in aquarium

Better yet, the Siamese algae eater can be found at almost any pet or fish store, are reasonably priced, and because of their temperament and resilience, are ideal for beginners.

Keep in mind, however, that these fish might consume algae, but they also produce their own waste. Don’t overload your tank with SAE (we will cover more on how many Siamese algae eaters per gallon later on).

SAE Behaviors

You will find that the behavior of your SAE will change according to its diet and environment, though they are rarely aggressive because of this. Siamese algae eaters also do not have swim bladders; a common trait of any bottom-dwelling fish is missing hydrostatic organs.

In other words, Siamese algae eaters will be in constant motion. If they did not keep swimming, they would not be able to maintain their buoyancy and would sink to the bottom of the tank. 

This is why they excel at being tank cleaners. All that darting around in search of their next meal also makes them rather exciting to watch.

Since these fish can live up to 10 years, you will notice distinct changes in their energy levels and schooling behaviors. Around 4-5 years, they start schooling more readily if there are other SAE in the tank. If not, they are perfectly fine living alone.

Siamese Algae Eater Size and Appearance

A true Siamese algae eater has a narrow, shark-like body that can reach up to 6 inches (15 cm) in length.

Siamese algae eater have either gray or golden scales paired with a thick black stripe down the side, running from the head all the way to the tail. Their fins are clear, save for the caudal (tail) fin, which has just a little black in it from the body stripe.

Sometimes, the black stripe will fade a little. This could be caused by a number of factors: mating displays, periods of high stress, or even as camouflage (which is highly uncommon in an aquarium setting).

The only difference between male and females is size. Around 3-4 years old, female SAE will grow about 30 percent larger in size than their male counterparts. Appearance stays the same, otherwise.

siamese algae eater

Now, let’s briefly return to size and growth. These fish can grow much faster than you would expect when in an appropriately sized tank. Their maximum length is about 6-7 inches (15-16 cm), but they usually do not get to that point if they are not in a large tank. That said, these are not fish made for small tanks. 5 gallon and 10 gallon tanks are far too small, and even 20 gallon tanks can be too cramped.

If you want your Siamese algae eater to be happy and healthy, then the recommended tank size is 30 gallons, at least 36 inches (91.4 cm) in length.

If you have more than one SAE, keep in mind that they school, so the more you have, the bigger the aquarium needs to be. This is particularly true for older Siamese algae eaters.

SAE vs. Flying Fox and Lookalikes

There are a lot of fish that look like the humble Siamese algae eater. Because of these lookalikes, some pet stores may have them mixed up. You might think that’s not a bad thing, but it will be when the algae eater you purchased doesn’t do its job.

These imposter fish are usually bought and sold by accident since there is a general misunderstanding about the differences of each fish species.

siamese algae eater vs flying fox

As mentioned earlier, the SAE (Crossocheilus Siamensis) is a smaller fish with clear fins. When you compare it to a flying fox fish (Epalzeorhynchos kalopterus), you will notice that the flying fox has colored fins, with black reaching through the tail (caudal) fin and also coloring the dorsal fin. 

The black stripe on the flying fox is thicker, and it also has a black band running along its entire back. So, when you compare the two visually, you can pick out a flying fox from its two black lines while an SAE has but one. Plus, flying foxes have flaps at the corner of their mouths. Siamese algae eaters don’t.

Another lookalike is the Chinese algae eater (Gyrinocheilus aymonieri). Though confusion between CAE and SAE happens far less often, it does happen. The Chinese algae eater has a much more ragged black stripe on both sides of its body, whereas Siamese algae eaters are more uniform. 

The tails of CAE are also spotted with black or brown, keeping unity with its dappled scales. Also, you will notice that while Chinese algae eaters look kind of like catfish, the Siamese algae eater is more like a shark in appearance.

The last imposter is actually very confusing for the untrained eye: the Cambodian logsucker, also known as the false Siamese algae eater (Garra taeniata or Garra cambodgiensis). 

Thai flying fox algae eaters
Thai Flying Fox Algae Eaters

Many people will buy these false SAE in stores because they are sold by the wrong name then realize that these fish are not scum suckers. Cambodian logsuckers look almost identical to Siamese algae eaters and flying foxes, with dark backs, black stripes along the side, and lightly colored fins. 

The one way to tell Cambodian logsuckers apart from the other fish is to note the shapes of their backs and bodies. They are much larger than SAE and flying foxes, and their dorsal fins are smaller. Additionally, their caudal fins are not striped.

Be sure to research some images that compare Siamese algae eaters to their imposters so you do not make a mistake when purchasing your SAE.

Siamese Algae Eater Diet

The last thing you want to keep in mind with all this talk of cleaning your tank of algae is that Siamese algae eaters need proper nutrition, just like any other kind of fish. 

Their name is an obvious hint to their main food choice—algae—but that does not mean that they are confined to that. In fact, without a balanced diet, your SAE might not live as long as you hoped.

For example, Siamese algae eaters will eat any kind of algae, but they tend to have a preference for green hair algae. For this reason, some fish keepers will even grow green hair algae to keep their SAE satisfied. 

Still, it is never a good choice to provide your Siamese algae eater with only algae. This will lead to vitamin deficiency and, ultimately, sickness and poor health. Also, if you give your Siamese algae eater a diet high in protein, they might start avoiding algae and will forage for more commercial sources.

That means you have to find a balance between algae wafers, catfish pellets, meats, and live food.

To do this, you can focus on algae and letting them forage, since that is their natural inclination. Supplement their diets with meatier items once in a while. The recommended proportion is 80 percent vegetables, 20 percent meat. 

That means that 80 percent of the time, your SAE is foraging for algae. The remainder is devoted to offering nutrient-rich sources of food.

You may have to experiment with the ratios a little bit to see which works best for your Siamese algae eater. Just be careful not to overfeed your fish.

Will SAE Consume Different Kinds of Algae?

Black beard, red, and hair green algae are all notoriously difficult to get rid of. Black beard algae, for example, can survive treatment from even the most potent of algaecides.

You might be at the end of your rope when it comes to black beard algae—but never fear. Your friendly SAE can help.

A real Siamese algae eater is going to make a beeline for that stuff. SAE absolutely adore black beard algae and will chow down on all kinds of hair algae, making them one of the most powerful cleaners in your fish tank.

Some fishkeepers have reported that their SAE are not eating black beard algae. There is usually a reason for this. 

If your aquarium lacks a number of live plants and has a high CO2 level, it will cause the algae, primarily black beard and green hair algae, to stiffen. This makes the algae very unappetizing to your SAE.

If that is the case, you can furnish the aquarium with live freshwater plants to provide the water with more CO2 and soften the algae. Your SAE will get to work soon after.

Ideal Tank Conditions and Habitat

Keeping Siamese algae eaters takes a bit more planning and work than having a tank with algae growth. Think back to where these fish live. With a preference for bottom-dwelling, it is better to have sand or other softer substrates at the bottom of the tank to prevent abrasion or other damage to their barbels.

You should also have plenty of plants. Not only will live plants help keep the water clean, they add entertainment and hiding spots for your fish. 

Of course, your SAE, being omnivores, may begin nibbling on plants. You might want to use fast-growing freshwater plants like hornwort or red root floaters, since they can recover rapidly when pieces are eaten.

Many fish owners who have SAE will also keep their tank covered. Siamese algae eaters may be bottom-dwellers who love hiding in caves, but they are also known jumpers. And they are very proficient at it. You will need to keep the tank permanently covered to prevent escape.

Keep the aquarium water around 75-79 degrees F (23-26 degrees C), and maintain a hardness of around 5-20 dH. The recommended pH level runs between 6.5 and 7.0, which is average for most fish. However, SAE can tolerate a slightly more flexible span of 6.0-8.0. SAE also do not have specific water flow needs, despite naturally living in rivers.

What Size Tank Do Siamese Algae Eaters Need?

Minimum Tank Size
20 Gallon 50%

The minimum size tank for a single SAE with tank mates is 20 gallon. This is due to their size and growth rate, as well as breeding and schooling habits. 

When keeping Siamese algae eaters, use this rule of thumb: You need 20 gallons for your first SAE and then an additional 10 gallons for every SAE added thereafter.

So if you have two SAE, you need at least 30 gallons of water for them to live. To see SAE showing their true nature, the ideal group is 4-6 Siamese algae eaters. However, you don’t need to keep more than one Siamese algae eater if you don’t want to.

What About Tank Mates?

Siamese algae eaters are very peaceful fish and not aggressive. Because of that, the list of potential tank mates is too long. For that reason, let’s focus on what fish you should avoid if you have a Siamese algae eater.

Mainly, you want to consider what other bottom-feeders are going to be in the tank. Most bottom-dwellers, like red tail sharks, can be territorial and will harass the SAE. The most peaceful bottom-feeder to pair with SAE are corydoras, a genus with a bunch of different species.


Avoid cichlids, since they are aggressive fish to begin with and need to be kept in isolated tanks. The exception to this is angelfish.

Guppies, danios, and tetras are also smart pairings, because they are neither territorial nor aggressive; but they are schooling fish and require a lot of room. Barbs and gouramis are bigger, yet they are non-aggressive, so they work well with SAE too.

SAE Alternatives: Other Recommended Algae Eaters

Can’t find an SAE in the stores? Worried your tank is not large enough? Have other fish that might not get along with a Siamese algae eater? Don’t worry. You can find other algae-busting alternatives. Here are some recommended SAE alternatives to add to your tank:

  • Plecostomus (or Pleco): A full-grown pleco can sometimes grow over a foot long, which is why the common variant is the bristle nose pleco, which only gets to about 5-6 inches long (14-15 cm). These are the fish that love clinging to the glass walls of the aquarium and are most active at night.
  • Oto cats: A variety of catfish that stays below 2 inches in length, making them ideal for small aquariums. They happily eat all kinds of algae and will not bother live plants.
  • Cherry shrimp: With bright, cherry red bodies, these shrimps are great for cleaning algae and nothing else. However, they are very finicky in terms of their habitat and can have adverse reactions to too much copper. They also require communities with placid fish.
  • Amano shrimp: Less finicky and more resilient than their brightly colored counterparts, these shrimp grow larger and will eat algae others shy away from. They also do well in more aggressive tanks. 
amano shrimp
Amano Shrimp

Of course, Siamese algae eaters are also one of the best fish at their job. If you can get them and keep them healthy, your tank will be super clean in no time. Best of all, some of the other algae eaters on this list can even be paired with SAE.

Common Siamese Algae Eater Diseases

It is worthwhile to say that, while there are few diseases to which only SAE are prone, there are a number of diseases that can affect a broad range of freshwater fish, algae eaters included. 

There are a number of ills and ailments that give very blatant symptoms, so you can visually diagnose what is wrong with your Siamese algae eater or other fish. Others are less noticeable, making it difficult to figure out what that problem could be.

That is why it is important to know what SAE are vulnerable to and what to look out for, so you can take care of the problems early, before the sickness becomes fatal. Siamese algae eaters are mainly affected by skin flukes, fungal infections, bacteria and parasites.

The most common disease seen in freshwater fish is called Ich. The disease is caused by a parasite that causes the fish to break out with small whitish dots across the body. 

You might notice your fish behaving strangely, such as rubbing its body against the substrate or plants. You can prevent Ich from striking by regularly changing the water and making sure the environment is clean.

Remember: Dirty water is just as harmful to fish as it is to humans and other animals. Be sure to clean your fish tank about every two weeks. That should reduce the chances of your fish getting sick from toxic build-up and parasites.

Preventative care is also far less expensive and twice as effective then waiting for your fish to get sick and giving them medication. What do we mean by preventative care? 

Think about your own health! In order to not get sick, you make sure you get plenty of physical activity, eat healthy and quality foods, and you get enough sleep. Well, your Siamese algae eaters (and all other fish) are the same way.

Cheap food given at irregular intervals will cause constipation and/or bloating, which can lead to swim bladder disorder and other organ dysfunctions.

Also, you need to consider what and who is in your tank. There are some decorations that might be made with toxic ingredients, such as paints, that will be dangerous to your fish. 

If you plan on adding new fish to the tank, always quarantine them for a few days. This will help determine if the new additions are healthy or if they are carrying some kind of disease that would harm your Siamese algae eater and its tank mates.

What Should I Do For a Sick SAE?

The best practice for any sick fish is to put it in a separate quarantine—or “hospital”—tank that does not have any decorations or gravel. If the disease is affecting the whole tank, don’t bother quarantining every fish separately. Just treat the entire aquarium.

Go to the pet store or order medication online to treat your fish for whatever you think it has. Make sure you read the instructions for the medication thoroughly. 

Some treatments are very strong and can destroy the beneficial bacteria living in the tank or even affect the quality of the water. This is why quarantining is often the best option if only one or two fish are affected.

Give your sick SAE (or other fish) time to recover in the hospital tank before placing them back in their home.


So, that is everything you need to know about the Siamese algae eater. Are you ready to get one? Despite everything in this article, the SAE is not hard to care for. Once you have one or two in your tank, you will have the perfect partner for keeping the tiny ecosystem clean of algae—and you’ll have fun watching them, too!

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