The Siamese algae eater is the best algae fighter in the aquarium, including black beard algae. An active and hardy fish for community tanks.
Overview
The Siamese algae eater (Crossocheilus siamensis) is a freshwater fish from the Cyprinidae family, recognized as the most effective biological algae control in the aquarium hobby. This species, known as the "true SAE," is capable of eating even black beard algae (BBA) — a type of algae that most other fish will not touch.
Crossocheilus siamensis originates from fast-flowing rivers and streams of Thailand and the Malay Peninsula. In the wild, the fish inhabits clear waters with rocky bottoms and abundant vegetation. Adults reach 10-15 cm in length and can live 8-10 years with proper care.
The true Siamese algae eater can be distinguished from similar species by its characteristic black stripe that runs from the tip of the snout all the way to the end of the caudal fin — specifically extending onto the tail fin lobes. The edges of this stripe are jagged and uneven. In Crossocheilus oblongus, the stripe ends at the base of the tail, while in the false SAE — Garra cambodgiensis — the stripe is smooth with clean edges, and the fish does not eat red algae.
Tank Requirements
A minimum tank volume of 100 liters is required for keeping the Siamese algae eater. This fish is an active swimmer that needs plenty of open space to move around. Optimal water parameters are: temperature 24-26°C, pH 6.0-7.5, and general hardness (GH) 5-20.
The tank must be equipped with a lid — Siamese algae eaters are prone to jumping, especially in stressful situations or when water parameters change abruptly. Water flow from the filter is welcomed, as the fish naturally inhabits rivers with moderate to strong currents.
The tank setup should include live plants, driftwood, and rocks. These elements provide shelter and simultaneously serve as a substrate for algae growth — the fish's natural food. The substrate should be fine to medium-grained, without sharp edges, as the fish frequently forages along the bottom.
Feeding and Diet
Despite its reputation as an algae eater, you should not rely solely on aquarium algae as a food source. As Crossocheilus siamensis ages, it becomes less interested in algae and increasingly eager to accept other foods. Therefore, the diet should be varied from the start.
The staple diet should consist of high-quality tablets and granules for herbivorous fish, as well as spirulina-based foods. Regularly offer blanched vegetables: zucchini, cucumber, spinach, and lettuce leaves. For protein supplementation, frozen or live brine shrimp and bloodworms are suitable — offer these 1-2 times per week.
It is important not to overfeed — a well-fed algae eater loses motivation to clean the tank of algae. Feed once or twice daily in small portions that are consumed within 2-3 minutes.
Care and Maintenance
Keeping the Siamese algae eater is not particularly difficult and is suitable even for beginner aquarists. Weekly water changes of 25-30% and good filtration form the foundation of successful care. The filter should provide both mechanical and biological filtration while also creating moderate water flow.
Test water parameters regularly, especially during the first months after setting up the tank. Monitor nitrate levels — they should not exceed 20-30 mg/l. Water aeration is essential, as the fish originates from oxygen-rich river waters.
Pay attention to the condition of fins and skin. Under good conditions, the Siamese algae eater has robust health and rarely falls ill. The average lifespan in an aquarium is 8-10 years.
Compatibility
The Siamese algae eater is a peaceful fish well suited for community tanks. The best tankmates are similarly sized calm species: tetras, rasboras, corydoras, and peaceful barbs. Avoid housing with large aggressive cichlids and slow-swimming fish with flowing fins, as they may become targets of fin nipping.
It is best to keep Siamese algae eaters in groups of 3-5 individuals. In a group, the fish behave more calmly and display less territorial behavior, which is sometimes observed in solitary individuals as they age. It is not recommended to keep them with other bottom-dwelling algae eaters such as the red-tailed black shark or Chinese algae eater, as territorial conflicts may arise between them.
Breeding
Breeding Crossocheilus siamensis in a home aquarium is virtually impossible. This is one of the species that extremely rarely reproduces in captivity. Commercial farms in Southeast Asia use hormonal injections to stimulate spawning, which is neither accessible nor practical for hobbyists.
In the wild, spawning occurs during the rainy season when fish migrate upstream. Replicating such conditions in an aquarium is not feasible. Sexual dimorphism is minimal: adult females are slightly fuller-bodied than males, but distinguishing sex in young fish is practically impossible.
All specimens available in the trade are either wild-caught or farm-raised using hormonal stimulation. If you are specifically interested in breeding aquarium fish, consider species that are more accessible for this purpose.