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Flying Fox Fish: A Detailed Care Guide

Flying Fox Fish: A Detailed Care Guide

The Flying Fox Fish, also known as ‘Epalzeorhynchos kalopterus‘, is a vibrant and beautiful fish species that can add a tremendous amount of color and liveliness to your aquarium. These fish are native to Southeast Asia and belong to the Cyprinidae family.

While they are a popular choice for aquarium enthusiasts, it’s important to note that they can exhibit aggressive behavior towards their own and other species. As such, it’s crucial to provide them with a large tank and plenty of hiding spots.

In this guide, we will discuss how to properly care for your Flying Fox Fish, covering everything from tank setup and water quality to diet and behavior. With these tips, you can create a healthy and stimulating environment that allows your fish to thrive.

Flying Fox Species Overview & Natural Habitat

  • Common name: Flying Fox Fish
  • Scientific name: Epalzeorhynchos kalopterus
  • Care level: Moderate
  • Size: 4-6 inches (10-15 cm)
  • Lifespan: Up to 10 years
  • Temperament: Aggressive
  • Diet: Omnivore
  • Group size: 1 per tank, not to be kept with their own species
  • Minimum tank size: 55 gallons (208.19 L)
  • Tank level: Bottom dweller
  • Water temperature: 68-79°F (20-26ºC)
  • Water pH levels: 6.0-7.5
  • Water hardness: 5-12° GH

Flying Fox Fish are endemic to southern Thailand, Java, Sumatra, and the Malay Peninsula. They inhabit highly oxygenated and swift-flowing rivers and streams, often with rocky bottoms. They are found among rocks and vegetation near the banks in their natural environment.

When kept in aquariums, these fish should have a well-oxygenated, heavily planted environment and plenty of space. They live in rivers or streams and migrate to forested areas during the monsoon season, which is why large tanks are advised. 

Flying Fox Appearance & Size

The Flying Fox Fish can range in size from 4 to 6 inches (10-15 cm) and has an elongated body and a sleek, flattened stomach. Its lower body displays a yellowish-white shade while its dorsal area varies in color from olive to dark brown. Additionally, a distinct black stripe runs horizontally across the fish’s body from its eyes down to the base of its cordal fin, complemented by a gold-colored stripe above it.

A true Flying Fox Fish has a red iris and translucent anal, dorsal, and ventral fins at the front, with a thick black band lining the edges.

One of the distinctive features of the Flying Fox is its pair of long, whisker-like barbels that extend from its mouth. These barbels help the fish to locate food on the bottom of the tank. 

However, it’s important to note that the Flying Fox is often confused with its close relative, the Siamese Algae Eater (Crossocheilus siamensis), which has a similar appearance.  One way to tell them apart is by the black horizontal line.  The Flying Fox has a solid black horizontal stripe, whereas the Siamese Algae Eater has a black horizontal stripe with a zig-zag edge.

Flying Fox Personality & Behavior

The Flying Fox Fish is a highly active and aggressive species that should be cautiously handled. They are known to fight with other fish in the tank, as they establish a hierarchy and can become very territorial. 

They can be quite boisterous. You can provide them with plenty of plants, driftwood, and rock work to hide in. Since they naturally inhabit rivers and streams, they need a strong current in their aquarium to mimic the wild. If there is insufficient water flow, this can cause irritation and aggression in the Flying Fox Fish.

Flying Fox Average Lifespan

The Flying Fox Fish can live for up to 10 years in captivity and even longer in the wild. They must be kept in a healthy environment with proper care and nutrition to reach their maximum age. Regular check-ups are recommended to ensure their water parameters stay within a suitable range.

Flying Fox Fish Care & Tank Set Up

Flying Fox Fish require specific environmental conditions in order to thrive, but with a solid understanding of their needs, caring for them can be a relatively straightforward process. By providing the appropriate tank setup and regularly maintaining water quality, you can ensure your Flying Fox Fish remain healthy and vibrant.

Tank Size

The Flying Fox Fish ‘Epalzeorhynchos kalopterus’ is an active species and should have a tank size of at least 55 gallons (208.19 L). This gives them enough room to move around and explore their environment. You may also consider adding a lid to the tank, as Flying Fox Fish are notorious for jumping out of tanks.

Water Parameters

The ideal parameters for Flying Fox Fish are as follows:

  • Water temperature: 68-79°F (20-26ºC)
  • Water pH levels: 6.0-7.5
  • Water hardness: 5-12° GH

These parameters should be tested regularly using a reliable water test kit. Minor changes in the water chemistry can have negative effects on your fish. Perform regular water changes to ensure that the tank’s parameters remain consistent. 

What To Put In The Tank

You need to replicate the natural environment of the Flying Fox Fish in your aquarium. Decorate the tank with rocks, driftwood, and plenty of plants to create hiding places for your fish. 

It’s crucial to keep in mind that these fish have a tendency to jump out of the water, even when there are floating plants present. Therefore, it’s important to ensure the tank is equipped with a tight-fitting lid and that there are no visible gaps that could potentially allow them to escape. 


Fine rounded gravel is an excellent option as it allows for easy cleaning and doesn’t interfere with the fish’s behavior or health. Adding some large pebbles can create hiding spots and visual interest in the tank, but make sure they are not too sharp or rough, which could cause injury to your fish. 

Soft sand is another alternative that can be beneficial, particularly for those fish that prefer to dig and burrow. The key is to ensure that the substrate is not too coarse or abrasive, as this can harm the delicate barbels of Flying Fox Fish. Ultimately, a combination of these substrates can create a dynamic and natural-looking environment for your fish to thrive in.


Decorations will help provide hiding spots and shaded areas to help these fish feel secure and reduce stress. A combination of driftwood, including branches and roots, can offer natural hiding spots while also serving as a substrate for algae growth. 

Water-worn rocks and boulders, bog wood (abonos), and cobbles can also be incorporated to create visual interest and mimic natural riverbed environments.

Ideal Plants

In nature, Flying Fox Fish are found among rocks and vegetation near the banks; they need a well-oxygenated and heavily planted environment. While floating plants are ideal to provide shade and a comfortable hiding place, these bottom dwellers will feel even more at home with the addition of carpet plants in their tank. 

The lush vegetation not only adds aesthetic appeal but also creates a sense of security for these fish, which typically spend a lot of time near the substrate.

Some plants to consider are Anubias, Microsorum, Bolbitis, Java Ferns, Moneywort; Java Moss or Vallisneria Spiralis.


Provide a bright light to allow for the growth of algae, as they rely on this for nutrition. Use a sandy, gravelly substrate to simulate their natural environment. It should have a few large particles, pebbles, or stones, as they are bottom dwellers. 


They inhabit areas with free-flowing waters. Therefore, you should provide them with a current in the tank by adding an air stone or filter outlet. Depending on the tank’s bioload, the water should be replaced 25-50% every two weeks. Use a gravel cleaner to remove any food or waste that has settled on the substrate.

Flying Fox Fish Tank Mates

These fish tend to be very aggressive and territorial towards their own kind, so keeping more than one in the same aquarium is not recommended. They can be kept with other active, medium-sized, semi-aggressive species such as danios, rasboras, large tetras, and cyprinids.

When placing them in a community tank, they should be the last and final fish added to prevent them from becoming territorial and dominating the tank.

Tank Mates To Avoid

Flying Fox Fish do not coexist well with slow-moving fish, as they may pick on them and cause stress. Bottom dwellers such as barbs, catfish, and shrimps should be avoided, as well as any fish small enough for the Flying Fox to swallow whole. 

Shy, peaceful fish may become stressed when living in the same tank as this active species. 

It is also recommended to add fish of similar sizes, so they do not become victims of the Flying Fox Fish’s aggression.

Flying Fox Fish Food & Diet

Flying Fox Fish are omnivorous and will happily eat plant-based and meaty foods. They also enjoy small invertebrates, such as daphnia or brine shrimp. When it comes to feeding your fish, a combination of high-quality flakes or pellets and live, frozen, or freeze-dried foods is best.

They also feed on algae and other aquatic plants, so provide them with plenty of algae-based snacks. You should also include spinach, lettuce, zucchini, cucumber, and shelled peas into their diet. 

Although they are bottom dwellers, they usually move to midwater to feed on biofilm that forms on rocks and decorations. Feed them small amounts twice a day and ensure that any food not eaten is removed from the tank, as it will cause water quality issues.

To maintain a healthy and active lifestyle, vary your Flying Fox Fish’s diet. Feeding them the same food daily can lead to malnutrition and poor appetite. You should also be mindful not to overfeed them, as this can cause digestive problems and even death.

If you’re keeping a group of Flying Fox Fish, it may be necessary to spread the food out so each fish can get a fair share.

Breeding Flying Fox Fish

Breeding in captivity is incredibly difficult and has yet to be accomplished. Although commercial breeding is done using hormones in some countries via professional hatcheries, if a pair is found in the wild, they typically spawn. There is still limited information about this species and its breeding habits.

Flying Fox Fish FAQs

What Is The Temperament Of The Flying Fox Fish?

The temperament of the Flying Fox Fish is generally peaceful, but they can become territorial and aggressive towards other fish of the same species or those with similar body shapes.

What Is The Difference Between The Flying Fox Fish And Siamese Algae Eater?

The Flying Fox Fish (Epalzeorhynchos kalopterus) is known for its smaller and more slender body shape compared to the Siamese Algae Eater (Crossocheilus oblongus). Additionally, the Flying Fox Fish has a distinctive black stripe that runs along the length of its body, and 1 pair of barbels near its mouth while the Siamese Algae Eater has a more irregular zig-zag black stripe with 2 pair of barbels near its mouth.

The Flying Fox Fish is also more aggressive and territorial, while the Siamese Algae Eater is generally peaceful.

How Big Do Flying Fox Fish Get?

Flying Fox Fish typically grow to be around 4-6 inches (10-15 cm) in length when fully mature. However, their size can vary depending on a variety of factors such as diet, water quality, and tank size. Providing them with a healthy and spacious environment can help them grow to their full potential.

Wrapping Up

The Flying Fox Fish is a stunning and active freshwater species perfect for the experienced aquarium keeper. Although they can be territorial, these fish make a wonderful addition to any tank if they are kept with other semi-aggressive species. With the right environment and care, the Flying Fox Fish can live up to 10 years and provide endless hours of enjoyment.

I’m Elle, the founder of FishHQ. I created this website to share knowledge, tips, and inspiration for beginner hobbyists to help them create a healthy, happy, and vibrant environment for their fish to thrive. Read more...