Chinese Algae Eater
Sucking Loach, Indian Algae Eater, Siamese Algae EaterFamily: Gyrinocheilidae Gyrinocheilus aymonieriPhoto Wiki Commons: Courtesy Pseudogastromyzon. Public Domain
The Chinese Algae Eater is a workhorse when it comes to its job... eating algae!
The Chinese Algae Eater Gyrinocheilus aymonieri is a one of the best known aquarium fish. It is found in large areas of Southeast Asia and southern parts of China. It was first exported to Germany in 1956 for the aquarium trade, but In its native countries it is used as a food fish.
This fish is very much desired by many aquarists. Though not the most beautiful of fishes, it is mainly appreciated for its ability to keep the aquarium free of algae. It does a great job at that when it's a youngster but as it matures its diet preferences begin to change. It will start looking for a meatier food source, like small crustaceans and even the slime coating of other fish, and it also starts enjoying the easier foods supplied by its keeper. There are several other surprising aspects about keeping this fish besides a changing diet. These include its size, the number of very similar "look-alike" species, and its personality with its tankmates.
Normally it's available as a juvenile with a size of just one to two inches, but this fish gets much bigger. It has been recorded reaching up to a whopping 11 inches (28 cm) in the wild, though captive specimens are usually much smaller. They are mature at about 4 1/2 inches (12 cm) and seldom exceed 5 1/4 inches (13 cm) in the aquarium. We have seen them at 5 inches, but we have never seen one approaching 11 inches.
The wild coloring of this fish is quite variable. Most often they will have yellowish sides and are browner on top. There is a notable black stripe running along the sides from the tip of its "nose" to its tail. This stripe is often broken and there can be black spotting along its back and on the tail fin. There are a number of color morphs available as well, like the popular gold variety called the Golden Chinese Algae Eater. Other varieties include albino, marble, and lecustic forms.
The Chinese Algae Eater belongs to the family Cyprinidae, which is commonly known as the Carp family. It has an under slung mouth but unlike many cyprinids, it does not have barbels. The mouth forms a sucking disk that is perfect for anchoring to a surface especially in fast moving water. This is its most important characteristic favored by aquarists. It uses this disk to remove biofilm and algae. Thus it is also well known as the Sucking Loach or Sucking Catfish, even though it is neither a loach nor a catfish. There are a multitude of other common names for it as well including Algae eater, Indian Algae Eater. Siamese Algae Eater, Siamese Headbreather, Sucker loach, Honey Sucker, and Biforated Carp.
When young, the Chinese Algae Eater does fine in a community aquarium, busily going about its business of greedily foraging algae. It will feed from the glass sides of the tank, the plants, the substrate, and any decor. When it gets older however, not only its diet, but also its behaviors can change. As it matures it can start to defend a territory. It can continually harass tankmates and will especially display high levels of aggression towards similar-looking fish. Keeping a group of 5 or more individuals can help help alleviate aggression. They will establish a pecking order within their group, but this can help reduce aggression towards other species.
The eventual size, as well as its compatibility with tankmates, will need to be taken into account when choosing a tank for this fish. As juveniles a 30 gallon aquarium is minimum, but when they reach their adult size 55 gallons or more will need to be provided, especially if you are keeping a group. The best tankmates for this fish are active robust cyprinids, characids, or similar species that hang out in the upper regions of the aquarium. It also helps if this fish is introduced to the aquarium last, so it won't try to claim the entire tank as its territory.
This fish prefers hiding places in wood, rocks and plants. Since they graze on algae most of the time when young, some sunlight on the aquarium to promote the algae growth is appreciated. Though they prefer algae, you can occasionally substitute crushed lettuce or spinach. The quality of the water needs to be maintained with regular changes, and as they are river fish, some water movement is needed as well. Also, they won't work in the cold. If the temperature in the aquarium drops below 69° F (20° C) they will stop eating algae!
For more Information on keeping this fish see:
Guide to a Happy, Healthy Freshwater Aquarium
- Size of fish - inches: 11.0 inches (27.94 cm)
- Minimum Tank Size: 55 gal (208 L)
- Temperament: Semi-aggressive
- Aquarium Hardiness: Moderately hardy
- Temperature: 77.0 to 82.0° F (25.0 to 27.8° C)
- Aquarist Experience Level: Intermediate
- My Aquarium - Enter your aquarium to see if this fish is compatible!
The Chinese Algae Eater Gyrinocheilus aymonieri was described by Tirant in 1883. They are found in large areas of Southeast Asia and southern parts of China. This species has been described from Cambodia in the mountains of Samrong Tong and Kampong Speu province as well as the Mae Klong, Chao Phraya, Mekong and Dong Nai river basins of Cambodia, Yunnan province in China, Laos and Thailand.
This cyprinid was first exported to Germany in 1956 for the aquarium trade, but In its native countries it is used as a food fish. It is one of three currently three described species in the Gyrinocheilus genus. The other two are the Spotted Algae Eater Gyrinocheilus pennocki and the Borneo Algae Eater Gyrinocheilus pustulosus. Only the G. aymonieri is common in the aquarium trade, while its two cogenitors are rarely seen.
This species is listed on the IUCN Red List as Least Concern (LC). It has a wide distribution but some populations have declined in some parts of its range, such as Thailand. It is considered threatened in China and Viet Nam, but is not believed to have declined enough throughout its range to be of major concern at present. It is used as a food fish in its native countries.
These cyprinids inhabit large and medium sized waterways such as lakes and rivers, as well as flooded fields. They are often found in the clear, shallow waters of inflowing streams and tributaries that are exposed to the sun, so the substrate is covered with a dense biofilm. They will migrate into deeper waters depending on the season.
The mouth of this fish forms a sucking disk that is perfect for anchoring to a surface, especially in fast moving water. Substrates consist of boulders, gravel, sand and areas littered with submerged driftwood and tree roots. This fish adheres to these solid surfaces with their 'sucker' type mouth. They are an aufwuchs grazer, meaning they feed on algae, periphyton (a mixture of algae, small bacteria and detritus), and phytoplankton (a micro algae), and they also consume zooplankton and insect larvae.
- Scientific Name: Gyrinocheilus aymonieri
- Social Grouping: Unknown
- IUCN Red List: LC - Least Concern
The Chinese Algae Eater has an elongated body with an under slung mouth. The mouth forms a sucking disk that is perfect for anchoring to a surface especially in fast moving water. Unlike many cyprinids it does not have barbels but it does have multiple small tubercles or "thorns" around the mouth. These tubercles are more numerous and pronounced on males in spawning condition. These are large fish growing to lengths of 11 inches (28 cm) in the wild, though captive specimens are usually much smaller. They are mature at about 4 1/2 inches (12 cm) and seldom exceed 5 1/4 inches (13 cm) in the aquarium. They have an average lifespan of 5 to 10 years in captivity with proper care.
Not the most beautiful of fishes, the body of the Chinese Algae Eater is plain with a notable black stripe from the tip of its "nose" to its tail. Though their color is quite variable, they are often yellowish on the sides, more brown along their back, and have a yellow eye. The stripe is often broken, and there can be black spotting along the back and at the base of the dorsal and caudal fin. There are a number of color morphs available as well, like the popular gold variety called the Golden Chinese Algae Eater. Other varieties include albino, marble, and lecustic forms.
There are a number of similar looking species that can be confused with this fish. Some of the similar species are peaceful, shoaling fish and include commonly available cogenitors. These "look alikes" include the laterally striped Crossocheilus spps such as the Siamese Algae Eaters C. atrilimes and C. langei, the Flying Fox Epalzeorhynchos kalopterus, and the Stone Lapping Minnow or Cambodian Logsucker Garra cambodgiensis.
Don't confuse the Chinese Algae Eater with the similar looking Siamese Algae Eater or Red-algae Eater Crossocheilus langei. These are two distinctly different fish from two separate genera. Though both are algae eaters, the Siamese Algae Eater will eat a broader range of algae's including the black forms and the filamentous red forms. The Siamese Algae Eater lacks the distinct sucker mouth and its horizontal center stripe extends through the tail fin and has jagged edges. This fish is not as readily available to the aquarist and when it is, its a bit more pricey.
- Size of fish - inches: 11.0 inches (27.94 cm) - One rarely sees individuals exceeding 5 1/4 inches (13 cm) in home aquariums.
- Lifespan: 5 years - They have an average lifespan of 5 - 10 years with proper care.
The Chinese Algae Eater is a moderately hardy fish and easy to keep. However they do not always play well with others and can create a lot of stress in the tank. This fish is often obtained by aquarists to help control algae, but due to its size when fully grown and its aggressive tendencies, it is suggested for an aquarist with some experience. The quality of the water needs to be maintained, and they don't like a dirty substrate. As long as the tank is properly set-up and maintained these fish do very well with most levels of fish keepers.
- Aquarium Hardiness: Moderately hardy
- Aquarist Experience Level: Intermediate - Due to its size when fully grown size and its aggressive tendencies, it is suggested for an aquarist with some experience.
These fish are omnivorous. When young, the Chinese Algae Eater prefers an herbivorous diet of algae and vegetable matter, but they will eat live and flake foods as well. As they mature their diet preferences begin to change to a meatier food source, like small crustaceans and even sucking on the scales of fish.
In the aquarium offer a good quality flake along with fresh plant material or algae wafers. You can occasionally substitute crushed lettuce or spinach for algae, as well as shelled peas, cucumber and chopped fruits. Making a gel based food with a mix of these natural ingredients also works well. To keep it in top condition and in its best colors, supplement it's diet regularly with small live and frozen foods like bloodworms, brine shrimp, and Daphnia.
How often to feed these fish depends on the amount of algae in the tank and how often you feed your other fish. As such, match feeding levels to algae levels. In general these fish will do best when offered regular food daily, with algae wafers provided about every other day. Most aquarists report that this fish stops eating algae as soon as it discovers fish food.
- Diet Type: Omnivore - Predominantly herbivorous when young, they can eat flakes or pellets containing proteins and vegetables.
- Flake Food: Yes
- Tablet Pellet: Yes - Algae wafers work best for this fish.
- Live foods (fishes, shrimps, worms): Some of Diet
- Vegetable Food: Most of Diet
- Meaty Food: Some of Diet
- Feeding Frequency: Daily - Depends on the tank and other inhabitants. In general offer regular food daily, with algae wafers provided about every other day.
These fish are easy to care for. The most important thing is that they always have clean, well-oxygenated water. Aquariums are closed systems and regardless of size all need some maintenance. Over time decomposing organic matter, nitrates, and phosphate build up and the water hardness increases due to evaporation. Replace 25 - 50% of the tank water at least once a month. If the tank is densely stocked 20 - 25% should be replaced weekly or every other week.
During water changes a vacuum siphon can be used to clean the substrate of any excess foods and other waste. Make sure not to remove the biofilm on rocks, decor or on the viewing panes of the tank. A regular or magnet algae scraper works well to keep the glass clear.
- Water Changes: Monthly - If the tank is densely stocked the water changes should be done every other week.
The Chinese Algae Eater is an active fish that will spend most time on the bottom of the aquarium. For juveniles a 30 gallon aquarium is the suggested minimum, but when they reach their adult size a 55 gallon tank or larger will need to be provided, especially if you are keeping a group. This fish as fairly hardy and will adapt to most aquarium conditions but it's best to introduce this fish into a biological mature tank as they do require pristine water.
An undergravel filter is a great choice for these fish as it creates high oxygen through out the tank as well as reducing the waste. Adding a canister filter or power head to the setup will make the proper current for this fish. These fish can jump if given the chance so make sure to have a tight fitting cover.
These fish aren't really too concerned about the decorations in the tank. An aquarium best suited to this fish would have lots of plants and other decor. If the tank is to resemble it's natural habitat, a soft sand and gravel mix would be best for the substrate. A lot of smooth water-worn rocks and stones should be scattered throughout. They are very inquisitive and like to explore so make sure to have a lot of caves and crevices. A couple pieces of driftwood and some twisted roots will make a great place to retreat. Since they graze on algae most of the time, some sunlight on the aquarium to promote algae growth is appreciated.
- Minimum Tank Size: 55 gal (208 L)
- Suitable for Nano Tank: No
- Substrate Type: Any
- Lighting Needs: Moderate - normal lighting
- Temperature: 77.0 to 82.0° F (25.0 to 27.8° C)
- Range ph: 6.0-8.0
- Hardness Range: 5 - 19 dGH
- Brackish: No
- Water Movement: Moderate
- Water Region: Bottom - This fish stays mostly on the bottom and sides of the aquarium.
When young they are a good community fish. The active young Algae Eater will go about its business of greedily foraging algae. When it gets older however, it can start to defend a territory and can continually harass tankmates. Adult specimens are generally indiscriminately aggressive towards everything so are often best just kept alone. However keeping a group of 5 or more individuals can help help alleviate aggression. They will establish a pecking order within their group, but the cantankerous behavior in their group can help reduce aggression towards other species.
They are best kept with fast moving fish if they are in a community tank. Good tankmates for this fish are active robust cyprinids, characids, or similar species that hang out in the upper regions of the aquarium. They also do well with African Cichlids. It helps if this fish is introduced to the aquarium last so it won't try to claim the entire tank as its territory.
- Temperament: Semi-aggressive - Younger fish are not as aggressive as adults.
- Compatible with:
- Same species - conspecifics: Yes - They are best kept in groups of 5 or more.
- Peaceful fish (): Monitor
- Semi-Aggressive (): Monitor
- Aggressive (): Threat
- Large Semi-Aggressive (): Monitor
- Large Aggressive, Predatory (): Threat
- Slow Swimmers & Eaters (): Monitor - Will try to suck on slow swimming fish.
- Shrimps, Crabs, Snails: Safe - not aggressive
- Plants: Safe
Chinese Algae Eaters have multiple small tubercles or "thorns" around the mouth. These tubercles are more numerous and pronounced on males in spawning condition.
Not much is known about the breeding behaviors of these fish. To our knowledge they have not been intentionally bred in the aquarium or commercially, though there have been reports of accidental breeding. See the description of breeding of cyprinids in: Breeding Freshwater Fish: Cyprinids
- Ease of Breeding: Unknown - Breeding has only occured accidentally to date.
Chinese Algae Eaters have a scaleless belly and are prone to disease, so take caution when introducing these fish to an established tank. They are also very sensitive to medications used to treat many diseases so a separate hospital tank is needed. Cold water and condition changes can also cause stress and can make them prone to disease. With any additions to a tank such as new fish, plants, substrates, and decorations there is a risk of introducing disease. It's advisable to properly clean or quarantine anything that you want add to an established tank prior to introduction, so as not to upset the balance.
These fish are very resilient but knowing the signs of illness, and catching and treating them early makes a huge difference. An outbreak of disease can often be limited to just one or a few fishes if you deal with it at an early stage. The best way to proactively prevent disease is to give your fish the proper environment and a well balanced diet. The closer to their natural habitat the less stress the fish will have, making them healthier and happy. A stressed fish will is more likely to acquire disease. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.
The Chinese Algae Eater is very popular and readily available in pet stores and online, and are moderately inexpensive.
- Animal-World References: Freshwater Fish and Plants
- Gyrinocheilus aymonieri (Tirant, 1883) Siamese algae-eater, Fishbase.org
- Gyrinocheilus aymonieri, The IUCN Red List of Threatened Species
- Dr. Rudiger Riehl and Hans A. Baensch, Aquarium Atlas Vol. 1, Publisher Hans A. Baensch, 1991
- Joseph S. Nelson, Fishes of the World, Wiley, 2006.
- David Alderton, Encyclopedia of Aquarium and Pond Fish , DK Publishing, Inc., 2005.
- Dick Mills, Aquarium Fish (101 Essential Tips), DK (Dorian Kinglsey) Adult, 2004.
- Dr. Herbert R. Axelrod, Aquarium Fishes of the World, TFH Publications, 1998