Information, Cyprinids, Freshwater fish, Other cyprinids, Species

Siamese algae eater “flying fox” (Crossocheilus siamensis)

The Siamese Algae Eater is a vibrant and active species of fish. Despite its popularity, many novice and intermediate fish keepers still need to learn about the distinctive qualities and requirements of the Siamese Algae Eater.

This in-depth article will delve into the fascinating world of this species, covering everything from its origin and appearance to its behavior, tank conditions, and diet. 

Whether you’re a seasoned fish keeper or just starting, this article will provide all the information you need to care for your Siamese Algae Eater properly. So sit back, relax, and prepare to be enthralled by the fascinating world of the Siamese Algae Eater!


Scientific Name: Crossocheilus siamensis
Common Names: Siamese algae eater, Siamese Siamese flying fox
Life Expectancy: Up to 10 years
Adult Size: Up to 6 inches (15 cm)


HabitatRivers and streams in Southeast Asia
OriginThailand and the Malay Peninsula
Care LevelEasy
TemperamentPeaceful and social
DietHerbivorous – algae, vegetables, and sinking pellets
Tank LevelBottom and middle levels
Minimum Tank Size30 gallons (113 liters)
Water pH6.5 – 7.5
Water Temperature75 – 79 °F (24 – 26 °C)
Water Hardness5 – 12 dGH
LightingModerate to high
Tank MatesPeaceful community fish, avoid keeping with aggressive or fin-nipping species

Fun Fact Corner

One fun fact about the Siamese Algae Eater is that it is a highly active and playful species. These fish are known for their curious and energetic behavior, and can often be seen swimming playfully throughout the tank. In addition to eating algae, they will also often play with decorations or toys in their tank, making them not only a useful, but also entertaining addition to any aquarium.


The Siamese Algae Eater, also known as Crossocheilus siamensis, hails from the freshwater rivers of Southeast Asia, specifically Thailand, Laos, Cambodia, and Indonesia. This fish has been a mainstay of the aquarium industry for decades because it thrives in the warm, slow-moving waters of its native habitat. 

Its ability to prevent algae growth in aquariums has made it a desirable addition to the tanks of many hobbyists. The Siamese Algae Eater was likely first brought to the aquarium trade from its native Thailand, but it is now commonly bred in aquariums worldwide.

Appearance & Size

The Siamese Algae Eater is a visually appealing species with its streamlined body and vibrant coloration. It has a slender, elongated body with a distinct black stripe running from its nose to the base of its tail.

This stripe is framed by a golden yellow color that glows brightly in the proper lighting. The species’ scales also have a metallic sheen, giving it a shimmering appearance as it swims through the water. 

The Siamese Algae Eater is a medium-sized species, with adults reaching 4-6 inches long. Because of its small size, it is suitable for most aquarium setups, as it does not require a large tank to meet its requirements. 

However, it is important to note that the Siamese Algae Eater is an active swimmer who requires adequate swimming space to prevent stress and maintain health.


The Siamese Algae Eater is a sexually monomorphic species, so it can be difficult to distinguish between males and females based solely on visual inspection. However, subtle differences in the shape and size of the fish can be used to determine gender, with females being slightly larger and rounder in shape. 

Furthermore, during breeding, males may develop more intense coloration and breeding tubercles, which are small bumps on their fins that can help identify their gender. It is important to note that determining the gender of Siamese Algae Eaters may not be necessary for the average hobbyist because the species is not typically bred in captivity but propagated through the aquarium trade. 

On the other hand, understanding the differences between male and female fish can provide insight into their behavior and help promote their overall health and well-being.


The Siamese Algae Eater is known for its dynamic and social behavior, making it a great addition to community aquarium setups. It is a schooling species in its natural habitat, spending most of its time swimming in close-knit groups with its kind. It is best kept in groups of at least six individuals in captivity to mimic its natural social behavior and prevent stress. 

This species is also a peaceful fish that gets along well with other peaceful fish of similar size. Despite its dynamic personality, the Siamese Algae Eater is not aggressive and should not be housed with larger or more aggressive species that could harm it.

The Siamese Algae Eater is known for its active feeding habits and social behavior. This species is a voracious algae eater, constantly searching for and consuming algae on aquarium surfaces. Its feeding habits are critical to its role in algae growth control, making it an important part of many hobbyists’ aquarium maintenance routines. 


It is critical to select compatible tankmates for the Siamese Algae Eater in terms of water conditions, size, and temperament. This species is generally peaceful and can be kept with other peaceful fish if the tank is large enough to accommodate all inhabitants.

The following are some suitable tankmates for the Siamese Algae Eater:

  • Other peaceful, non-aggressive fish species
  • Small schools of tetras, rasboras, or barbs
  • Catfish, such as Corydoras or Plecostomus
  • Other algae-eating species, such as otocinclus or crossocheilus siamensis
  • Snails, shrimp, and other invertebrates

It is important to note that the Siamese Algae Eater can be territorial with other fish species that resemble it, such as Crossocheilus siamensis. Only one specimen of each species should be kept in the same tank. 

Furthermore, the Siamese Algae Eater should be kept with less extensive, aggressive species that may bully or harm it. Hobbyists can create a peaceful and happy environment by choosing appropriate tankmates.

Tank conditions

The Siamese Algae Eater is a hardy species well-suited to life in captivity, provided its tank conditions are appropriate. The aquarium water should be clean and well-filtered, with a pH range of 6.0-8.0, a water hardness range of 5-19 dGH, and a temperature range of 72-82°F. Furthermore, the tank should have adequate aeration and a strong water flow to provide oxygen and prevent stagnant water buildup.

The Siamese Algae Eater is an active swimmer who needs plenty of space in the aquarium. A single specimen requires a minimum tank size of 30 gallons, with ten tank spaces needed for each additional fish. 

To provide the fish with a sense of security and mimic its natural habitat, the aquarium should include plenty of hiding places, such as rocks, caves, and plants.

The Siamese Algae Eater is not exceptionally light-sensitive and can thrive in various lighting conditions. However, adequate lighting is required to promote algae growth in the tank, which the fish will consume as a diet.


The Siamese Algae Eater is an omnivorous species, meaning it will consume plant and animal matter in its diet. In the wild, this species primarily feeds on algae and other aquatic plants, small insects, and other organic matter. In the aquarium, the Siamese Algae Eater should be fed a varied diet consisting of dry and wet food to ensure a complete and balanced nutrient profile.

Some good food options for the Siamese Algae Eater include:

  • Algae wafers
  • High-quality sinking pellets
  • Freeze-dried or frozen brine shrimp, bloodworms, or other small aquatic creatures
  • Blanched vegetables, such as spinach or lettuce

It is important to avoid overfeeding the Siamese Algae Eater, as this can lead to water quality issues and health problems. Feed the fish small portions several times a day, and remove any uneaten food promptly to prevent it from decomposing and contaminating the water.

By providing a diverse and nutritious diet, hobbyists can help to maintain the health and vitality of the Siamese Algae Eater and support its ability to perform its important role in the aquarium ecosystem.


Breeding the Siamese Algae Eater can be a challenging and rewarding experience for hobbyists who are committed to providing the right conditions and care. The species is not well-known for being a prolific breeder in captivity, but with patience and dedication, it is possible to breed these fish successfully.

Here are some tips to help you breed the Siamese Algae Eater:

  • Provide a spacious and well-maintained aquarium with stable water conditions, good filtration, and adequate heating.
  • Offer the fish a varied and nutritious diet to promote optimal health and condition.
  • Ensure the aquarium is densely planted, with plenty of hiding places and territories for the fish.
  • Ensure that the fish are housed in a compatible group with an appropriate ratio of males to females.
  • Observe the fish closely and look for signs of breeding behavior, such as the formation of a breeding pair, nest-building, and the laying of eggs.

Once breeding has been successful, it is important to monitor the developing eggs and fry carefully, and to provide appropriate care and nutrition to support their growth and survival. With proper care, the fry can be raised to adulthood and can then be used to start a new generation of Siamese Algae Eaters.

Breeding the Siamese Algae Eater requires patience, dedication, and a deep understanding of the species and its requirements. However, for hobbyists committed to this challenge, the rewards of successfully breeding these beautiful and fascinating fish can be truly rewarding.


The Siamese Algae Eater is generally considered a hardy fish species, but it is susceptible to diseases. Some common diseases affecting Siamese Algae Eaters include Ich, Fin Rot, and Velvet Disease.

It is important to maintain a clean and healthy tank environment to prevent these diseases, including regular water changes and monitoring water parameters. Good tank conditions and a balanced diet can also help to keep the fish healthy and prevent disease.

In case of an outbreak, it is crucial to consult with a veterinarian specializing in aquarium fish to determine the best course of treatment.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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