Algae Eating Cyprinids from Thailand and Neighboring Areas
(c) Copyright 1994 N. Frank and L. Sarakontu
[
Ed: There is a much more accurate and better HTML translation on the AGA
Version of this article, so you may wish to read it there.
Unique to this site,
here are some photos of two small SAE's in
my tank... and one big one amongst some rummy
nose tetras. -EO]
This article talks about five fishes from Thailand and
neighboring areas, including the elusive Siamese Algae Eater
(Crossocheilus siamensis) which is the only known fish to
effectively eat red (beard/brush) algae. The other four fishes
are (1) a very similar fish which we call the "false siamensis,"
(2) a more colorful relative - the Flying Fox (Epalzeorhynchus
kalopterus), (3) another Crossocheilus species and (4) the
Chinese algae eater. To the casual observer, all fish may look
the same at first. Even some reputable aquarium texts have
confused the real and false siamensis. A summary table is
included at the end to compare the distinguishing features among these
interesting fishes.
This slender algae eating barb is the only known fish that eats
red algae. It comes from the flowing waters of Thailand and the
Malay peninsula. It was first brought to Europe in 1962, but
became popular in the 1970's when its ability to eat red algae
was noticed. The fish is also known as Siamese Flying Fox, and
Siamese Fox. It previous scientific name was Epalzeorhynchus
siamensis. To those interested in the fine, but admittedly boring
details of taxonomy, the genus Crossocheilus differs from
Epalzeorhynchus by rhynal lobes (nasal lobes).
Description
It is a slender, grayish-brown fish with a distinctive black
horizontal stripe. Maximum length is 15 cm (6") and might be
obtained in two years, if the conditions are optimal. Normally
They grow slower and don't always reach that size in captivity.
They can live over 10 years. All the fins are transparent or
slightly milky without any yellow or reddish sheen. The black
band goes from nose to the fork of the tail and its edges are
zig-zagged. When a fish is stressed or fighting the black color
fades significantly. Underparts are silvery white and there is no
light stripe over the black, but the whole upper body is brownish
and every scale has a dark edge, which make the top look
reticular. Some dark scale edges might be seen under the black
stripe. It has a pair of thin, forward-pointing barbels but they
might be pressed against the cheeks when fish is swimming or
resting. The long black stripe is also easy to see in young
fishes, but the scale edge pattern and zig-zag edges are not
clearly visible until the fish reaches the length of 5-7 cm
(2-3"); the ones that are normally seen in European shops are
about 3-5 cm (1-2") long. Adult females are often slightly
fatter than males, no other sexual differences are known.
Behavior
It is an active and fast swimmer, which thrives best in schools
but can also be kept alone or in pairs. It is a strong jumper and
should not be kept in uncovered tank, because it will eventually
jump. Siamese Algae Eaters often chase one another but they
never get hurt in these fights.
C. siamensis has a peculiar resting position: it doesn't lie flat
on its belly but keeps its body propped up with its tail, pelvic
and pectoral fins. Young fish sometimes rest on broad leaves,
adult specimens prefer resting on bottom or dense, low plants
like Cryptocorynes. The swim bladder is not very developed, so
the fish can't stay in midwater but it must be in constant motion
or it sinks.
Needs
Siamese Algae Eater is not very demanding. Suitable temperature
is 24-26 C (75-79F). They can tolerate pH from 5.5 to 8.0, but
6.5-7.0 is ideal.
Hardness should be less than 20 dH. Water should be clean and
oxygenated, because they come from bright and fast-flowing
streams. They eat algae, including red algae and all kind of live
and prepared foods. It is very rare that they harm plants in
their tank if they are given enough green food. They also eat
algae when they are mature, but seem to prefer flake food.
Liisa's fish eat Duckweed (Lemna minor) but have never touched
any other plants. They haven't yet been bred in captivity, so all
the specimens are caught from nature. It appears that the fish
are seasonal and are not always available in the shops. Minimum
tank size for a pair of adult Siamese Algae Eaters is 100 liters
(25 gallons). The aquarium should be long and have lots of living
plants.
Compatibility
As they are not aggressive, they can be kept in any community
tank big enough. Their active behavior might stress some
sensitive species like dwarf cichlids and prevent them from
spawning. They should not be kept with Red-tailed Sharks
(Epalzeorhynchus bicolor) unless the aquarium is large and well
planted, because that species is very aggressive towards all its
relatives.
This algae eating barb strongly resembles the Siamese Algae
Eater. It comes from the same region and at least young specimens
can school together. These fish are often mistaken for real
Siamese Algae Eater and in Finland it is common to see some
specimens among a tankful of Siamese Algae Eaters. It seems that
the real Siamese Algae Eater is a rarity in US, and the "false
siamensis" is normally sold as Siamese Algae Eater. More
confusing is that many respected Aquarium books (e.g. Baensch
Atlas, Volume 1, english edition) present this fish as the
Siamese Algae Eater (Crossocheilus siamensis).
There is still some uncertainty regarding the true identity of
this fish. Markku Varjo states that it is the Siamese Stone
Lapping Fish (Garra taeniata Smith 1931), but other very
knowledgeable aquarists (including Heiko Bleher and Fumitoshi
Mori) believe it is some species of Epalzeorhynchus. More
information from Heiko will be forthcoming from the authors.
Description
At first sight this fish is just like the Siamese Algae Eater,
but they are easy to tell apart when you know what to look. The
black horizontal band does not go to the fork of the tail but
stops at the base of the tail and its edges are rather smooth.
When the fish is frightened the black stripe fades to light grey.
All fins except pectoral are yellowish and there are dark
markings on the dorsal fin. The rays near the base of the dorsal
fin are black and there is another dark band in the upper part of
dorsal. There is a distinctive narrow light stripe over the black
horizontal band and the dorsal region is solid grayish brown
without dark scale edges. The top area is also slightly darker
than Siamese Algae Eater. Sometimes bright red or pink is seen
around the mouth but it might disappear if the fish is stressed.
It has two pairs of barbels (unlike the Siamese Algae Eater). Maximum
length is reported to be 15 cm (6"). No sexual differences are
known, but the amount of red might depend on the sex of the fish.
In the orient, these fish are called "colorful flying fox."
Ironically, Crossocheilus siamensis is called "the one like
flying fox."
Behavior
Adult specimens are aggressive towards each other, otherwise like
Siamese Algae Eater.
Needs
"False siamensis" is more demanding on water quality than Siamese
Algae Eater. It needs very clear and oxygenated water, ideal
temperature is 24-26 C (75-79F) and the pH shouldn't get much
under 7. They eat some algae, but in nature they probably seek
small animals from algae growths. In aquarium they eat all kinds
of live and artificial foods. They have not been bred in
captivity. Minimum tank size for it is 80 liters (20 gallons).
Compatibility
Can be kept in any community tank. Adult specimens often get
aggressive toward each other, so there shouldn't be more than one
"false siamensis" in a tank. They might also harass related
species and other small bottom-dwellers like loaches, if the tank
is not big enough.
The Flying Fox is the most colorful of this fish group. For this
reason, it has gained popularity in the U.S. over Crossocheilus
siamensis and "false siamensis". It comes from the flowing waters
of Thailand, Sumatra and Borneo. Wholesalers sometimes deliver
this species as Siamese Algae Eater in Finland. This fish is also
known as Trunk Barb.
Description
Body and fin shape like two previous species. Thin specimens are
often pictured in the aquarium literature. The overall color is
warmer brown or even goldish and the black horizontal stripe goes
from nose to the fork of the tail like on Siamese Algae Eater,
but the part going through the tail fin in darker and broader.
There is a narrow golden stripe over the black. Dorsal, anal and
pelvic fins have indistinctive dark bands and bright white tips.
It has 2 pairs of barbels. Maximum length is reported to be 15 cm
(6"). No sexual differences are known.
Behavior
Same as previous species. Adult specimen is territorial and
aggressive towards its own kind.
Needs
Ideal pH is near 7, temperature 24-26C (75-79F). It eats all
kinds of live, prepared and plant foods. It has not been bred in
captivity. Minimum tank size 80 liters (20 gallons).
Compatibility
Flying Fox can be kept in a community tank, but it might chase
other fish viciously from its territory. There shouldn't be more
than one adult Flying Fox in a tank.
Crossocheilus oblongus (Cuvier and Valenciennes, 1842)
This is a close relative to Siamese Algae Eater, and it is
possible that specimens of this fish are sometimes found in
schools of Siamese Algae Eater or "false siamensis".
Description
Body shape and color are basically same as Siamese Algae Eater
and "false siamensis". All the fins are transparent and the black
horizontal stripe does not extend to the tail fin. The stripe
has smooth edges and the back is solid, not reticulated like on
Siamese Algae Eater. It has two pairs of barbels like Flying Fox.
Maximum length is 10 cm (4").
Behavior, needs and compatibility
Probably same as previous three species.
This Algae Eater belongs to family Gyrinocheilidae, although it
resembles both loaches and Algae Eating barbs. Its English name
isn't very accurate, because it comes from Northern India and
Thailand, not China. It is also called the Indian Algae Eater.
There are still some unclear points in the systematic
classification of this genus and it is possible that the species
most often imported isn't G. aymonieri but G. kaznakovi. There
are also two other species (G. pustulosus and G. pennocki).
Description
Chinese Algae Eater is a bottom-dweller. The most prominent
feature is a big suckermouth, which it uses for scraping algae
and clinging to objects. There is a special opening on the upper
part of the gill cover for the water intake so the fish can
breath without using its mouth. This same feature is seen on
Suckermouth Catfishes. The fish is light brown and there is a
dark grey or brown horizontal pattern on its side, which can be
either a zig-zag edged solid stripe or a row of separate spots
or anything between these two. Young specimens are more colorful.
There are some dark patches at the back and small brown spots at
the tail. All the other fins are transparent or slightly
brownish. Maximum length is 27 cm (11") but normally it doesn't
exceed 15 cm (6") in an aquarium. Females are larger and fuller,
adult males might show spawning tubercles on the head.
Behavior
It moves along all the surfaces of the tank scraping green algae
with its suckermouth. Older specimens prefer artificial foods and
are rather aggressive.
Needs
Chinese Algae Eater is not very demanding on water conditions: pH
may vary from 6.0 to 7.5 and the temperature from 22C (72F) to
28C (82F). Water should be well oxygenated, as it comes from
streams. It eats all kinds of foods, but must get enough algae
or plant food. It is reported that it will stop eating algae if
the temperature drops below 69 degrees F (20 deg. C). It has not
been bred in captivity. Minimum tank size 100 liters (25
gallons).
Compatibility
Young Chinese Algae Eaters can be kept in community, but adult
specimens can be aggressive to other fish. They most often attack
slow-swimming, flat-bodied fish and shouldn't be kept with them.
Distinguishing features
----------------------------------------------------------------
C.siamensis "False s." E.kalopterus C.oblongus G.aymonieri
-----------------------------------------------------------------
Horizontal
stripe:
- edge: zig-zag smooth smooth smooth uneven
- extend
to tail: yes no yes no
- lt.stripe
above: (sometimes) yes yes ?
-----------------------------------------------------------------
Dorsal
region: reticulated solid ?
(black edged grayish
scales) brown
-----------------------------------------------------------------
Fins
- dorsal: transparent dark dark bands trans- trans-
lower rays & white parent parent
& yellowish tips
- anal: " yellowish " "
- pelvic: " yellowish " "
-----------------------------------------------------------------
Mouth: small,non- clinging
clinging sucker
suckermouth mouth
(maybe with
red/pink)
-----------------------------------------------------------------
Barbels: 1 pair 2 pairs 2 pairs 2 pairs none
-----------------------------------------------------------------
References
Varjo, M. 1989: Akvaariomaailma. - WSOY. Porvoo.
Varjo, M. 1983: Levabarbi vai mika? - Akvaariolehti 3/83:16-19.
Petrovicky, I. 1988: Aquarium Fish of the World. - Arch Cape
Press, New York.
Mills, D. et al 1988: Tropical Aquarium Fishes. - Tetra Press,
NJ.
Axelrod, H. 1989: Atlas of Tropical Freshwater Aquarium Fishes. -
TFH, NJ
Riehl, R. and Baensch, H.A. 1989: Aquarium Atlas (Volume 1), -
MERGUS, Germany.
Smith, H.M. 1945: The Fresh-water Fishes of Siam, or Thailand.
Bulletin 188 - Smithsonian Institute, Washington D.C.
Liisa Sarakontu
The Krib
Fish/Animals
![[sketch]](falsae.jpg)
![[sketch]](fox.jpg)
![[sketch]](cae.jpg)
The Krib