FTC Disclosure: Fishpondinfo contains affiliate links, and, if you click on such a link and make a purchase, and I meet their minimal requirements, then I will be compensated.

Home Animal Index Fish Index Pond Index Master Index Contact
Pond Newsletter Message
Board Pond Book Calculator
Donate Interactive Fishpondinfo Stores Pond
Showcase Guestbook

Robyn's Algae Eater Page

Last Updated: 2/21/14

On the left is my false Siamese algae eater on 7/18/01. On the right is my real Siamese algae eater on 4/22/01.

Siamese Algae Eaters, False Siamese Algae Eaters, Flying Foxes, and Chinese Algae Eaters

This site was begun on 6/14/00.

Quick Information
Description and Varieties
Setup and Water Preferences
My False and Real Siamese Algae Eaters
Catching Algae Eaters
Links and Pictures

These groups of so-called algae eaters are often confused with one another. While these four species are often sold to eat algae, only the Siamese algae eater seems to make a difference in the concentration of algae in an aquarium. If Siamese algae eaters cannot be found, otocinclus are the next best choice for planted aquariums. See my otto page for more information. In large non-planted aquariums, common plecostomus may be used. In smaller or planted aquariums, there are some other smaller species of plecostomus that may work. Check out my pleco page for more information. There is also a chart comparing various algae-eating animals on my aquarium algae page.

New! There is now a video on my videos page of the Siamese algae eater in my 50 gallon tank.

Quick Information

Common and Scientific/Latin names:

Maximum length: 5-6 inches (exception = Chinese algae eater may grow to 11 inches)
Colors: Black on grey/white (exception = Chinese algae eater is more mottled brown or orange for the albino form)
Temperature preference: 73 to 80 degrees F
pH preference: 6-8
Hardness preference: Soft to moderate
Salinity preference: Low
Compatibility: Good with most other fish but may chase or harass other algae eaters (exceptions = Siamese algae eaters can get along with each other and Chinese algae eaters may harass fish besides other algae eaters)
Life span: ~10 years
Ease of keeping: Easy to moderate
Ease of breeding: Hard

Description and Varieties

Much confusion exists in discerning between the various fish sold under the name algae eater. See above under common and scientific names for information on those. While plecostomus, otocinclus, whiptails, and other fish are algae eaters, the fish sold as "algae eaters" generally do not eat algae if other foods are around. Unlike the previously mentioned fish as well, "algae eaters" are not catfish but cyprinids. The best site to visit to tell these various algae eaters apart is Algae Eating Cyprinids from Thailand and Neighboring Areas. The true Siamese algae eater or SAE is highly sought by aquarists with planted tanks because they are the only known animal that eats brush (hair?) algae which is called red algae although it is actually a brownish green. Unfortunately, most people actually end up with false SAE's which do not eat much algae. Along with the flying foxes and Chinese algae eater's (CAE's), false SAE's also prefer to eat fish food. The scientific name for the false SAE has apparently not been decided as of yet. Even the very good Baensch atlas only has an entry on the real SAE but the photo is of the more common false SAE (one of the few major errors in the books).

Siamese Algae Eater or SAE:
The true SAE has a jagged black horizontal stripe that goes all the way to the tip of the tail. All of the SAE's fins are clear. The black and white and their contrast are more intense than with the other algae eaters below.

False Siamese Algae Eater or false SAE:
The false SAE if usually found in shipments of true SAE (or the other way around). Unlike the SAE, the black stripe ends at the beginning of the tail. Often, if one goes to buy SAE's in a US aquarium store, they may in fact be all or mostly false SAE's. False SAE's may have some red around the mouth and a yellow tint to the fins. My false SAE had some nice gold and red on the dorsal fin. Mine was sold as a flying fox.

Flying Fox:
Just like the true SAE, the flying fox has a black horizontal stripe that goes all the way to the tip of the tail. Unlike the SAE, the edges of the stripe are smooth and not zagged. The flying fox may have some rainbow-like coloring on the fins. It is more pretty than the other fish mentioned on this page. The black horizontal stripe extends to the end of the tail like the SAE but it is much stronger and broader.

Chinese Algae Eater or CAE:

A bi-color CAE photo sent to me by Deb in August, 2005. See below under other people's fish photos for more.

The Chinese algae eater is Gyrinocheilus aymonieri. Unlike the SAE, false SAE, and flying fox, the CAE does not have a distinct black horizontal line. It is more mottled. The fish is more brown than black and white. The tail fin lacks any striping. The CAE also does not have any barbels unlike the other three fish. If you go to the average pet store that carries fish and ask for a fish that eats algae, probably half the time, you would have a Chinese algae eater foisted upon you. While these fish are a delight like the above fish, they have only a low to moderate desire to eat any algae. If fish food is available, it will compromise most of their food intake. Also, as Chinese algae eaters grow older, the may become nasty to other algae eaters or even other fish in the tank. Some may try to latch onto fat-bodied fish. Sometimes, though some individuals get along well with their tankmates. There is a very common albino (or gold) CAE which may be sold even more often then the regular gray CAE. The CAE does not zip around as much as the SAE, false SAE, and flying fox. It tends to do more sucking. CAE's normally stay under 6 inches but have the ability to grow to almost twice that length.

Setup and Water Preferences

All of these algae eaters are constantly on the move; therefore, they need a tank with lots of swimming room. The water should be near neutral with a pH between 6 and 8. The water should be soft to moderate in hardness. Temperatures can range from the low 70's degrees F and into the 80's. A temperature of about 76 degrees F is ideal.

All of these fish may display territorial and/or aggressive behavior to members of the same or similar species. For example, a flying fox may harass a SAE. SAE's are said to tolerate others of their own species (but not related species), at least while young. These fish all swim around virtually non-stop. This is due to an underdeveloped swim bladder. When there is more than one, they will chase each other and wear each other out.

All of these algae eaters come from swift moving waters in and around Thailand. They benefit from some current (from filters or power heads) in part of the aquarium.

When first introduced to a tank or while under stress, the black stripe on these fish can become washed out. After the stress passes, the normal coloration should return. These fish are known to jump so a good aquarium lid is a must.

On 12/6/03, Kam sent me an e-mail saying that his SAE killed some of his glass cats, usually during feeding time. Mine has been docile but quite the little (ok, BIG) pig at feeding time. Kam says his SAE loves to eat yellow squash and changes color from it. It can be messy though, leaving strings around (I have fed it to my plecostomus).

On 11/13/04, Julie informed me that her SAE's are aggressive towards anything with flowing fins and even ripped off some tails. Mine seems rather docile but I wanted to report observations from other people as well.


Females may be fatter. In the case of flying foxes and false SAE's, the males may have more color on their fins. The true SAE has no color on its fins. For CAE's, males may have tubercles on their head.


All the sources that I have read say that breeding has never occurred in captivity. Due to their flighty behavior, they are probably egg scatterers.

My False and Real Siamese Algae Eaters

My real Siamese algae eater on 12/28/02.

All of my false and real Siamese algae eaters have died as of 11/4/07.

I added a 2 inch false Siamese algae eater to my twenty gallon tank on 6/12/00. I designated him/her a she and named her Spaz. All she did was zip all over the tank. When I fed the white clouds with her, she zipped about trying to eat the food. After a few months of settling in, Spaz still mostly ate fish food but also would nibble at attached green algae. By 3/16/01, Spaz was about 2.5 to 3 inches long.

On 3/16/01, I went to my local aquarium store to buy lots of stuff but no fish. I had to however look at the fish. I found a tank of "siamensis" but looked at them and saw false Siamese algae eaters. But then, I saw that there were a few (maybe 6 of 100) that were real! So, I could not resist getting one. I named him or her baby Spaz, and he or she went into my twenty gallon tank with Spaz. Baby Spaz did not zip around as much as Spaz. This real SAE was only about 1.5" and hung out mostly in the water column with the white clouds in a stationary manner. The real SAE has a much stronger black line that goes to the end of the tail. The false SAE has many more colors. Within a day, the real SAE appeared to be nibbling on the tons of hair algae in my 20 gallon tank! By 3/21/01, baby Spaz was going up and down the glass eating attached green algae. I have seen no interaction or conflict between Spaz and baby Spaz!

Because my goldfish had all died in my 50 gallon tank, I re-did that tank. On 6/16/01, I moved all the fish I had in my 20 gallon tank into the newly setup 50 gallon tank. This included both my real and false SAE's. They were VERY hard to catch as they were much faster than the other fish I have had. Spaz was about 2.5. inches going on 3 inches, and Baby Spaz was up to about 2 inches. Spaz was the last of 17 fish that I caught during the move a few inches to the 50 gallon tank. Eight hours later, Spaz died. Apparently, he/she suffered internal injuries while I was trying to net him/her. I tried to be gentle but Spaz was, well, spazing (that means he/she was slamming into the glass and moving very fast). I felt very guilty. I was trying to provide the fish with a better home, and Spaz never got to enjoy that home. Spaz was perfectly healthy. Baby Spaz is settling in to his/her new home and enjoys the extra room. I just had to get another false SAE so I bought one on 7/8/01 and added it to the newly re-done 20 gallon tank. New Spaz is just like old Spaz but smaller. New Spaz was sold as a flying fox but his/her stripe ends at the beginning of the tail so he/she is not a flying fox or real SAE.

As of 8/21/03, my real and false SAE's are both about four inches long. Boy are they pigs! Both hog up all the fish food that they can and grow. Every once in a while, the real one will suck on some algae on the glass but not much!

On 4/16/06, Easter afternoon, I found my false Siamese algae eater dead along the front glass of my 20 gallon tank. He was not there earlier in the day. Spaz (or is it new Spaz? I call the real one new Spaz now) was measured at 4.75 inches long. He died three months before I would have had him/her for five years. New Spaz (previously baby Spaz), or the real Siamese algae eater was still fine in the 50 gallon tank and probably 6" long.

My real Siamese algae eater was always the first to come for food, and the biggest fish in my 50 gallon tank. In October 2007, he seemed to disappear. I found him dying on 11/3/07. He was dead by the morning of 11/4/07. He lost a lot of weight before dying. He was 5 inches long.

Catching Algae Eaters

Patricia sent the following message on 4/1/05:

"I sympathize with your efforts to catch Spaz and baby Spaz. Previously I had 6 flying foxes, which I had originally bought as algae eaters and kept for about 9 months. During that time they grew big, crashed about the tank disturbing the other fish and did not eat the algae - they had to go! Like you I had great trouble trying to catch them in my well established and well planted 200 litre aquarium. After several weeks of frustration and experimentation, I developed a very effective, stress-free (both for me and the fish!) method of catching the foxes, which I hope my be of interest to you. I made a rectangular wire frame (using wire from wire coat hangers) that was fractionally larger than the cross section of the tank (so that there was a tight fit against the sides of the tank). I then used black net (material bought from an ordinary sewing shop). First I stretched the material round the frame and sewed it into position. Each side I made a 'pocket' into which I slid a length of wood - this reinforced the tight fit where the net met the sides of the tank. There was some extra net hanging at the bottom that could be tucked around the plants to secure that no fish could swim under the 'bottom bar.' Now I had a screen 45 cm by 45 cm that fitted precisely and could be used to divide the tank into 2 areas. Then I marked an 18 cm diameter circle in the centre of the 'screen.' Next I cut and sewed a second piece of net to make a cone, 65 cm long with a diameter of 18 cm tapering to a diameter of 4 cm. I sewed the cone to the marked circle on the screen and finally cut an opening. Last of all I used a piece of thin string to tie the narrow end of the long cone, to make it like a 'cod end' on a trawl net. The cone part of the net was long so that when a fish swam down it, it was easy with one hand to close off a retreat. Any fish I wished to keep in the tank, I simply released the other side of the screen by pulling the string undone and letting the fish swim through. When I had a flying fox in the net, I lifted the narrow far end of the net over the side of the tank and released the fish into a bucket. The foxes were clever, and I had to 'chase' some of them with my hand, but they unsuspectingly tried to escape into the wide opening and down the long net, and I had all 6 flying foxes out of my tank within 20 minutes, without unduly disturbing the plants or other fish. I have attached a photo of the 'Brander flying fox' net, which I hope helps you understand what it looks like and how I made it."

Here is the photo:

Links and Pictures

Photos of my real and false SAE's:

Photos are listest from newest to oldest.

On 11/3/07, I found my real Siamese algae eater dying. I took one last photo of him:
Dying real Siamese algae eater

Real Siamese algae eater waiting in a bucket during the 50 gallon tank cleaning on 3/17/07. See the tank redo page for details. There is a small rosy barb next to him.

False Siamese algae eater in my 20 gallon tank (in the back) on 10/5/05. You can also see the male bristlenose pleco in the front right and the head of the young male paradise fish on the left.

The 50 gallon tank on 6/19/05. You can see the real Siamese algae eater in the middle.

Real Siamese algae eater in my 50 gallon tank on 2/28/04, playing among lots of rosy barbs.

Close up of my real Siamese algae eater on 10/18/03.

Real Siamese algae eater among the rosy barbs so you can get an idea of how big he is. The rosy barbs are full size. This is the 50 gallon tank on 10/18/03.

50 gallon tank where you can see the real Siamese algae eater cruising along on 9/22/03.

My real Siamese algae eater in my 50 gallon tank on 12/28/02. He is getting big! Those are rosy barbs around him.

My false Siamese algae eater in my 20 gallon tank on 7/18/01.

My real Siamese algae eater in my 20 gallon tank on 4/22/01.

Photos of Other People's Fish:

On 1/21/07, Tom sent me photos of his CAE's. He bought two of them and had assumed that they were true SAE's. Then, one turned gold/orange. He asked me about it, and I asked for photos. The photos confirm that the fish are CAE's. There are no albino (or orange or gold) SAE's but there are albino CAE's. They can also change from one to the other over time. Some CAE's are neat looking because they have orange patches as well as the normal coloration patches.
Normal CAE
Albino/orange/gold CAE - the fish still has a few patches of the darker coloration on the tail

On 8/7/05 and 8/14/05, Deb sent me these photos of her neat Chinese algae eater. The fish started out like a regular CAE but over time, has gained some orange areas indicating that one of its parents was probably an albino CAE. This is one beautiful fish!
Multicolored Chinese algae eater and a neon tetra and a lemon? tetra.
Chinese algae eater with a white tetra and a lemon tetra.
Chinese algae eater - top view.
Chinese algae eater - side view.

Links on "algae eaters":

Algae Eating Cyprinids from Thailand and Neighboring Areas - this is the site to go to if you want to know how to tell all these algae eaters apart; lots of information too!

Comparison of Algae Eaters - drawings showing how to tell SAE's from false SAE's from flying foxes. I have been informed that this site now has a lock/password on it which I verified. I guess they did not want us to learn the difference!

Siamese Algae Eater - info and lots of photos. This site too is no longer working. You can see an older version by going to archive.org and entering in the URL (http://www.usol.com/~sherlock/pets/siamensis.htm).

Thai Flying Fox - great false siamese algae eater photo and some information, note that the scientific name is wrong according to other sources. This site no longer works either. See the note in the previous link about using archive.org to access past versions of any web page. This link's URL was http://edge.net/~scraig.fox.htm.

Chinese Algae Eaters - some information and pictures; I think some of it is not accurate but do not know enough to say for sure. The pictures are not identified as the correct species nor does the information match the correct species.

Siamese algae eater information

If you know of any good links that I should add here, please e-mail me below.

Pet Link Banner Exchange:

There have been 51,181,002 file views (file views since 2006, page views before that) to Fishpondinfo from December 1, 2003 through August 17, 2019 (stats lost after that).
Page copy protected
against web site content infringement by Copyscape

Like Fishpondinfo
on Facebook Follow Fishpondinfo on

E-mail Robyn

Copyright © 1997-2023 Robyn Rhudy

Follow Fishpondinfo on
You Tube Follow Fishpondinfo on Instagram