Monday, 24 November 2008

In search of the true Siamese Algae Eater – get ready for the confusion!

So we know the true Siamese Algae Eater is the Crossocheilus siamensis which is often confused with the Flying Fox (Epalzeorhynchus kallopterus) and not so similar Chinese algae Eater (Gyrinocheilus aymonieri) as well as a fish known as the False Siamese Algae Eater (Garra cambodgiensis) which prefers fish food to algae.

                                Garra cambodgiensis

                        Epalzeorhynchus kallopterus

Often they are found in the fish store in a tank labeled – Algae Eaters which then house an array of fish that all look like a true Siamese Algae Eater.

Lots of shops mislabel these fish so Siamese algae eaters can also often be found under Flying Fox as well as other names.
The names in shops:
Algae Eater, Thai flying fox, Siamese flying fox, colorful flying fox, Epalzeorhynchos sp, trunk barb, Chinese catfish as well as an array of wonderful other names.

The only real gem for planted tanks is the Crossocheilus siamensis as this is the one that WILL eat brush algae (red algae) unlike most other fish…. All others also rather eat fish food and will not touch any algae.

So how do we tell them apart from a false Siamese algae Eater? Well the rule so far has been that the fins should be be all clear and the black horizontal line goes all the way to the tip of the tail. Sounds pretty easy but it seems one of those things so many get wrong…including publications (Baensch Atlas has a picture of a fake SAE instead of a true SAE in the book) and the internet has an array of wrong images listed under Siamese Algae Eater.

You may now smugly look at your tank and think ‘YES, I have a true siamensis’ but don’t get excited yet. Even if you have eliminated the chance of it being a flying fox, garra, or chinese algae eater there is more to come……

Intrigued as to how so many people can be confused a little research was needed…
It seems a whole group of fish who look very similar and near identical all swim in the same habitat and these are all caught up and labeled as one of the above names and sold in the shops.
So even in one tank in the shop you can have a mix of near identical fish who are actually different fish – yes it is so confusing but it gets even worse…

Here it comes… what you think may be a genuine Crossocheilus siamensis may actually be :-
Crossocheilus oblongus
Crossocheilus Langei
Crossocheilus atrilimes
Crossocheilus citripinnis

Yip these guys all swim around together in a habitat and believe me they all look like the real deal…but don’t act like the real deal when it comes to Algae.

                              Crossocheilus oblongus

                             Crossocheilus Langei

                           Crossocheilus atrilimes

Note that in images the coloration varies depending on stress as well as lighting etc.

There is a whole art to telling these guys apart which comes down to shading in a certain light, the exact millimeters of the horizontal stripe as well as the barbels or lack of. To make matters worse the one and only TRUE named Crossocheilus siamensis very very rarely is imported and nearly does not exist in our tanks.

So who is the imposter you thought was your true Siamese algae eater?

If you are lucky it is the Crossocheilus Langei which I believe we all label as and know as the true Siamensis – these guys are the only real brush algae eaters. All the others prefer fish food….

If you are unlucky you have the Crossocheilus atrilimes who favors soft plants and moss which makes sense to me now…. some people report their SAE eating moss etc. whilst other say they don’t touch theirs.

If you have a Siamese Algae Eater and are curious as to which one you really have now here is an excellent link:

After a head breaking hour I have discovered that I have 2 x Crossochelius Langei & 1 x Crossochellus Oblongus & 1 x Crossochellus citripinnis

Two of mine I believed to be Siamensis - the back one is a Citripinnis and the front on is a Langei (note the coloring is the same but the snout is different)


Patrice said...

I like those fish! They are just awesome.
Nice blog BTW!!!

Patrice from

cory said...

Just recently purchased 6 of these for my 6ft tank..they are fantastic little fish it's like watching 6 little Hoovers cleaning everything in their path
Enjoy reading your blogs keep up the good work


Ava said...

Jess, how are you supposed to tell one from the other? Some of them look so similar!

Jess said...

Hi Ava,

If you want the true algae eating one (C. Langei) then look out for a dark blotch under the abdomen and litle barbles on the front then you can't go wrong.


Ava said...

I'd like to ask you a more specific question. Can you write to me at Thanks!


Fischfutter said...

If it were the only problem with Siamese Algae Eater...