Siamese Algae Eater (SAE)
Crossocheilus oblongus
The Siamese Algae Eater (Crossocheilus oblongus), universally known as SAE, is the utilitarian legend of planted fishkeeping. Modest in appearance — a silver-grey torpedo body divided by a single sharp black stripe that starts from the nose and entirely crosses the caudal fin —, it is hailed for one specific reason: it is one of the very rare fish in the world capable of devouring the dreaded Black Beard Algae (BBA) and filamentous algae. Constantly inserted in aquascaping layouts, it is a tireless worker, although as an adult (15 cm / 6 inches) it can develop an annoying propensity for laziness.
Wassertemperatur
24 - 26 °C
pH-Wert
6 - 7.5
Wassertyp
Süßwasser
Tankfüllstand
Unten
Erwachsenengröße
15 cm
Mindesttankvolumen
>= 150 L
Mindestgruppe
>= 3
GH
5 - 15 dGH
KH
2 - 7 dKH
TDS
95 - 295 ppm
Leitfähigkeit
148 - 461 uS/cm
Artbeschreibung
Geographical Origin and Habitat: Mainland Southeast Asia. Inhabits the flowing waters of major river basins (Chao Phraya, Mekong) and shaded forest streams, typically with bottoms made of sand, gravel, and smooth pebbles, covered by a thick film of sun-grown algal biofilm.
Taxonomy and Morphology: Member of the Cyprinidae family. Streamlined torpedo body, silvery gray, crossed by a typical zig-zag black band extending continuously from the mouth to the extreme tip of the transparent caudal fin (key trait to distinguish it from false SAEs). Features an inferior mouth with barbels adapted for scraping surfaces. Reaches 15 cm (6 inches).
Social Behavior: Extremely active, vigorous, and gregarious when young. Loves to rest in a unique position: propped like a tripod on its lower pectoral fins and caudal fin, resting on rocks or broad leaves. Growing up (over 10 cm) it can become lazy, solitary, and sometimes boisterous toward conspecifics, chasing them for territorial disputes.
Coloration and Sexual Dimorphism: Color contrast is essential and clean: brownish-olive back, silvery flanks, and the distinctive, jagged central longitudinal black stripe. Sexual dimorphism is absent in young specimens; in fully adult females (2-3 years), the abdominal region is noticeably more convex and rounded compared to sleeker males.
Pflege, Zucht und Mitbewohner
Aquarium Setup: Mature, plant-dominated tank of at least 120 cm (4 feet) in length. Loves strong current (wavemakers) and water saturated with dissolved oxygen. Needs a soft substrate and large solid surfaces (large river stones, big bogwood roots, and Anubias leaves) to graze on algae and rest mid-water. Aquarium strictly covered (they are formidable jumpers).
Diet and Feeding: Legendary tireless grazer of Black Beard Algae (BBA) in its juvenile stage. However, it is an opportunistic omnivore: as it grows, it learns that commercial pellet or flake food is easier to obtain than algae, stopping its work. To keep the tank clean, food feedings must be targeted and reduced. Supplement with blanched zucchini.
Water Quality: Very adaptable and robust regarding parameters: pH between 6.0 and 7.5, temperature from 24.0 to 26.0 °C, and hardness (GH) from 5.0 to 15.0. The fundamental and absolute requirement, however, is excellent water purity (low nitrates and phosphates) and dynamic water circulation preventing asphyxic buildups.
Compatibility and Cohabitation: Excellent for dynamic Asian planted community aquariums (alongside Danios, Rasboras, Corydoras, Loaches). Absolute ban: never place adult specimens in tanks with large, slow, round cichlids with mucous skin (Angelfish, Discus). Nocturnal SAEs will try to feed on their skin mucus, causing severe ulcers and fatal stress to the cichlids.
Aquarium Breeding: Spontaneous reproduction is virtually impossible in private home aquariums. Mild dimorphism and unknown stimulating requirements block the process. The global market is supplied by millions of specimens artificially reproduced with hormone injections in immense fish farming vats in Thailand and Indonesia.
Risks and Diseases: The hardiness of this cyprinid makes it invulnerable to common diseases, but it is highly sensitive to hypoxia (low oxygen levels): it will be the first fish to gasp at the surface if the filter fails or during high summer temperatures. A major risk is fatal escape from an improperly closed lid and obesity induced by excessive commercial food.
Geografische Herkunft und Verbreitung
Mainland Southeast Asia. Inhabits the flowing waters of major river basins (Chao Phraya, Mekong) and shaded forest streams, typically with bottoms made of sand, gravel, and smooth pebbles, covered by a thick film of sun-grown algal biofilm.
Ursprung
Süd- und Südostasien
Fischprofil
- Temperament
- Territorial
- Generally peaceful and industrious, they spend most of their day minding their own business and grazing on algae. They are very active and their constant darting around can sometimes annoy more sedate fish. Older individuals can sometimes become mildly territorial or lazy, preferring prepared foods over algae. Overall, they are considered excellent, peaceful cleanup crew members for the planted community tank.
- Diät
- Omnivore
- Famous for their appetite for algae, they are one of the few species that will eat black beard algae and hair algae. While algae is a significant part of their diet, they are omnivores and must be supplemented with sinking pellets, algae wafers, and blanched vegetables like zucchini. They will also readily accept meaty frozen foods like bloodworms and brine shrimp. A balanced diet prevents them from becoming reliant solely on prepared foods and ignoring algae.
- Lebenserwartung
- 8-10 years
- Erwachsenengröße
- 15 cm
- Geschlechterverhältnis
- Group
- They can be kept individually or in small groups. When young, they school loosely together, but as adults, they may become slightly territorial with each other. If keeping a group, it is best to have 3 to 5 individuals or more to disperse any potential squabbling. The exact sex ratio is unimportant and difficult to determine anyway.
- Fütterungsfrequenz
- Twice daily
- They should be fed once a day with a balanced diet if the tank lacks sufficient algae growth. If there is plenty of natural algae in the aquarium, supplemental feeding can be reduced to a few times a week. It is important to ensure they are getting enough to eat, but overfeeding will cause them to ignore the algae they are meant to clean. Observing their belly fullness can help gauge if they are eating enough.
- Bioload
- Medium to High
- The Siamese Algae Eater has a moderate bioload, as they are active and eat continuously throughout the day. They require efficient filtration to manage their waste output, particularly in planted aquariums where they are often kept. Regular water changes and good tank maintenance are necessary to keep the environment clean. Due to their potential adult size, the bioload increases significantly as they grow.
- Fluss
- Strong
- Native to streams and rivers, they appreciate moderate to high water flow and high dissolved oxygen levels. A powerhead or strong filter current simulating a riverine environment keeps them active and healthy. They enjoy swimming against the current and often rest on broad leaves or smooth rocks in areas of higher flow. While they adapt to calmer waters, some current is highly beneficial.
- Sprungrisiko
- Yes
- They are strong, fast swimmers and are notorious jumpers, particularly when first introduced to a new aquarium. A tight-fitting, secure lid is absolutely essential to prevent them from jumping out. Escapes are common if there are any gaps around filter intakes or heater cords. They may also jump if chased by a tankmate or if water parameters become unfavorable.
- Reproduktion
- Impossible (hormone-induced)
- Breeding the Siamese Algae Eater in a home aquarium is extremely rare and has rarely, if ever, been documented without hormonal intervention. They are commercially bred in large numbers using hormone injections on fish farms. There are no known specific triggers or conditions to induce spawning in typical aquarium settings. Sexing them is also very difficult, making targeted breeding efforts almost impossible.
- Kompatibilität & Tankkameraden
- Community
- They are generally peaceful and make great additions to community aquariums with similarly sized, non-aggressive fish. They can be safely housed with tetras, rasboras, gouramis, and peaceful bottom dwellers. However, as they mature, they can sometimes become a bit boisterous or territorial towards their own kind or similar-looking fish like flying foxes. They should not be kept with slow-moving, flat-bodied fish, as they may occasionally attempt to graze on their slime coats.
- Tankfüllstand
- Bottom
- They are highly active fish that utilize all levels of the aquarium, but they spend the majority of their time at the bottom and middle levels. They can constantly be seen grazing on the substrate, rocks, driftwood, and plant leaves. They will quickly dart to the surface during feeding time. Providing plenty of surfaces for them to graze on is essential for their enrichment.
Wissenschaftliche Modelle & Parameter
FishBase
Zugang zu den offiziellen wissenschaftlichen Daten der Art
FishBase v25.04Daten synchronisiert am: 15.06.2026
- Trophäenniveau
- 2 ± 0 se
- Belastbarkeit
- Hoch (weniger als 15 Monate)
- Phylogenetische Einzigartigkeit (PD50)
- 0.5
- Bayessche Längen-Gewichts-Beziehung
- a = 0.00813, b = 3.05
- AnfälligkeitGeringe Anfälligkeit (10 / 100)
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