Siamese Algae Eater (SAE)

Geographic Origin and Biotope: 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.

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 Tankmates: 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 Reproduction: 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.