Siamese Algae Eater – Crossocheilus oblongus

The Siamese Algae Eater (Crossocheilus oblongus), often called an SAE, is one of the most popular freshwater algae-eating fish in the aquarium hobby. Known for grazing on black beard algae, hair algae, biofilm, and surface growth, this active species is a valuable addition to planted aquariums and larger community tanks.

Siamese Algae Eaters are hardy, active swimmers that do best in clean, well-oxygenated aquariums with plenty of open swimming space. They are especially popular with planted tank keepers who want a natural algae grazer that will not damage healthy live plants.

Key Features

• Excellent freshwater algae grazer
• Known for eating black beard algae and hair algae
• Peaceful to semi-active community fish
• Great for planted aquariums and aquascapes
• Active swimmer that enjoys open space
• Best kept in groups of 3 or more when space allows

Care Guide

• Scientific Name: Crossocheilus oblongus
• Common Name: Siamese Algae Eater
• Care Level: Easy to moderate
• Temperament: Peaceful to semi-active
• Adult Size: Approximately 5–6 inches
• Minimum Tank Size: 30 gallons minimum; larger recommended for adults or groups
• Tank Level: Bottom to midwater
• Water Temperature: 72–79°F
• pH Range: 6.0–7.5
• Hardness: Soft to moderate
• Diet: Omnivore with strong algae-grazing behavior

Why Choose a Siamese Algae Eater?

Siamese Algae Eaters are highly valued because they are one of the few commonly kept aquarium fish known for grazing on black beard algae. They also feed on hair algae, biofilm, and leftover foods, making them a useful part of a balanced aquarium cleanup crew.

They should not be used as the only method of algae control, but they can be very helpful when combined with proper lighting, balanced nutrients, regular maintenance, and good filtration. Juveniles often graze more heavily on algae, while adults may need more supplemental foods as they mature.

Ideal Tank Setup

Siamese Algae Eaters do best in a stable aquarium with strong filtration, good oxygenation, moderate water movement, and open swimming areas. Driftwood, smooth rocks, plants, and hardscape provide grazing surfaces and help create a natural environment.

A 30 gallon aquarium is the minimum starting point, but larger tanks are recommended as they grow. Because they are active swimmers, they need more space than smaller nano algae eaters.

Compatible Tankmates

• Peaceful tetras
• Rasboras
• Danios
• Rainbowfish
• Corydoras catfish
• Peaceful barbs
• Gouramis with caution
• Angelfish with proper space
• Snails

Tankmates to Avoid

• Aggressive cichlids
• Large predatory fish
• Very small nano fish that may be stressed by activity
• Similar-shaped fish if the aquarium is crowded
• Chinese Algae Eaters in most community tanks
• Overcrowded bottom-dwelling setups

Diet & Feeding

Siamese Algae Eaters naturally graze on algae, biofilm, and surface growth, but they still need a balanced diet. Offer algae wafers, sinking pellets, vegetable-based foods, blanched zucchini, spinach, cucumber, and occasional frozen foods such as brine shrimp, daphnia, or bloodworms.

As Siamese Algae Eaters mature, they may rely more on prepared foods and less on algae. A varied diet helps support healthy growth, activity, and long-term condition.

Care Tips

• Provide strong filtration and good oxygenation
• Offer open swimming space
• Use driftwood, rocks, and plants for grazing surfaces
• Supplement algae grazing with wafers and vegetables
• Keep with peaceful, active community fish
• Avoid confusing true Siamese Algae Eaters with similar-looking species

Siamese Algae Eater vs. Similar Fish

True Siamese Algae Eaters are often confused with Flying Foxes, False Siamese Algae Eaters, and Chinese Algae Eaters. These fish can look similar, but their behavior, adult temperament, and algae-eating ability may be different. Siamese Algae Eaters are especially valued because they are one of the better-known aquarium fish for grazing on black beard algae.

Frequently Asked Questions

Do Siamese Algae Eaters eat black beard algae?
Yes. Siamese Algae Eaters are one of the better natural algae-grazing fish for black beard algae, especially when young and actively grazing. Algae control still works best with proper lighting, nutrients, filtration, and regular maintenance.

Are Siamese Algae Eaters aggressive?
They are generally peaceful to semi-active, but they may chase similar-shaped fish or become pushy if crowded. A properly sized aquarium with open swimming space helps reduce issues.

Are Siamese Algae Eaters good for planted tanks?
Yes. Siamese Algae Eaters are popular in planted aquariums because they graze algae and biofilm without usually damaging healthy live plants.

Are Siamese Algae Eaters beginner-friendly?
They can be beginner-friendly in a properly sized, stable aquarium, but they are best for aquarists who can provide enough space, good filtration, and compatible tankmates.

How big do Siamese Algae Eaters get?
Siamese Algae Eaters can reach approximately 5–6 inches as adults, so they need more space than smaller algae eaters.

What size tank does a Siamese Algae Eater need?
A 30 gallon aquarium is the minimum starting point, but larger aquariums are recommended for adults or groups because they are active swimmers.

Do Siamese Algae Eaters need to be kept in groups?
They can be kept singly or in groups, but groups of 3 or more can work well in larger aquariums with enough swimming space and hiding areas.

What do Siamese Algae Eaters eat?
They eat algae, biofilm, algae wafers, sinking pellets, vegetable-based foods, blanched vegetables, and occasional frozen foods. Adults should be supplemented with prepared foods.

Are these fish available for shipping?
No. Live fish are available for in-store purchase or local pickup only at Tropical Treasures Wyo in Cheyenne, Wyoming.

Available at Tropical Treasures Wyo

Siamese Algae Eaters are active freshwater algae-grazing fish for planted aquariums, aquascapes, and larger peaceful community tanks. Visit Tropical Treasures Wyo in Cheyenne, Wyoming, to shop algae eaters, freshwater fish, schooling fish, shrimp, snails, live aquarium plants, fish food, filtration supplies, and aquarium care products. Live livestock is available for in-store purchase or local pickup only.

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