Chinese Algae Eater

Sucking Loach, Indian Algae Eater, Siamese Algae Eater

Family: 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 highly desired by many aquarists. Though not the most beautiful fish, it is appreciated for its ability to keep the aquarium free of algae. As a youngster, it does a great job at that, but its dietary preference will change as it matures. Adult Chinese Algae Eaters will look for meatier foods such as small crustaceans and even the slime coating of other fish. Adults will also start enjoying the easier foods supplied by their keepers. Other surprising aspects of keeping this fish, besides its changing diet, 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

Habitat: Distribution / Background

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 found 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, the 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 1 of 3 currently described species in the Gyrinocheilus genus. The others 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 cogenitors are rarely seen.

This species is listed on the IUCN Red List as Least Concern (LC). It has a wide distribution though 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 to be of major concern at present. 

These cyprinids inhabit large and medium-sized waterways such as lakes, rivers, and flooded fields. They are often found in the clear, shallow waters of inflowing streams and tributaries that are exposed to the sun and where 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 uses its 'sucker' mouth to adhere to these solid surfaces. 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

Description

The Chinese Algae Eater has an elongated body and an underslung mouth that  forms a sucking disk perfect for anchoring to hard surfaces in fast-moving water. Unlike many cyprinids, it does not have barbels, but it does have multiple small tubercles or "thorns" around its mouth. These tubercles are more numerous and pronounced on males in spawning condition. Chinese Algae Eaters 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 fish, 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 the back, and have yellow eyes. The stripe is often broken, and there can be black spotting along the back and at the base of the dorsal and caudal fin. A number of color morphs are available as well, like the popular gold variety called the Golden Chinese Algae Eater. Other varieties include albino, marble, and lecustic forms.

A number of similar-looking species can be confused with this fish. Some 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 Siamese Algae Eater or Red-algae Eater Crossocheilus langei. Though similar in appearance, 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 algaes, including black and filamentous red forms. The Siamese Algae Eater lacks the distinct sucker mouth, and its horizontal center stripe has jagged edges and extends through the tail fin. This fish is not as readily available and a bit more expensive.

• 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 to 10 years with proper care.

Fish Keeping Difficulty

The Chinese Algae Eater is moderately hardy 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 adult size and its aggressive tendencies, this fish is recommended for an aquarist with some experience.

Foods and Feeding

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 dietary preferences begin to shift toward meatier foods. Mature Chinese Algae Eaters will eat small crustaceans and even suck on the scales of other fish.

Offer a good quality flake food 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. A gel-based food made from a mix of these natural ingredients also works well. To keep the Chinese Algae Eater in top condition and to develop its best coloration, supplement its 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: Occasionally
• 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 - Depending on the tank and other inhabitants, offer regular food daily, with algae wafers provided about every other day.

Aquarium Care

These fish are easy to care for provided 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 water hardness increases due to evaporation. Replace 25 to 50% of the tank water at least once a month. If the tank is densely stocked, 20 to 25% should be replaced weekly or every other week.

During water changes, a vacuum siphon can be used to clean the substrate of 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, water changes should be done every other week.

Aquarium Setup

The Chinese Algae Eater is an active fish that will spend most of its time on the bottom of the aquarium. For juveniles, a 30-gallon aquarium is the suggested minimum, but a 55-gallon tank or larger will be need to house adults, especially when kept in a group. This fairly hardy fish 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 levels throughout the tank and reduces waste. Adding a canister filter or power head to the setup give this fish the proper current. These fish can jump if given the chance, so make sure to have a tight-fitting cover.

These fish aren't too concerned about the decorations in the tank. An aquarium best-suited to this fish has lots of plants and other decor. To help the tank resemble the Chinese Algae Eater's natural habitat, use a soft sand and gravel mix substrate, and scatter a lot of smooth, water-worn rocks and stones throughout. These inquisitive fish 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, postition the aquarium so that it receives some sunlight to promote algae growth.

• 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.

Social Behaviors

When young, they are good community fish. The active young Algae Eater will mind its own business, greedily foraging for algae. When it gets older, however, it can become territorial and may harass its tankmates. Adult specimens are generally indiscriminately aggressive towards any companions, so they are often best kept alone. However, keeping a group of 5 or more individuals can help alleviate aggression. The group will establish a pecking order, and the cantankerous behavior within the group can reduce aggression towards other species.

In a community tank, they are best kept with fast-moving fish. Good tankmates 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. Introducing the Chinese Algae Eater to the community tank last will also help curb its impulses toward territorial aggressiveness.

• 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

Sex: Sexual differences

Chinese Algae Eaters have multiple small tubercles or "thorns" around the mouth. These tubercles are more numerous and pronounced on males in spawning condition.

Breeding / Reproduction

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. For a general description of breeding cyprinids, see: Breeding Freshwater Fish: Cyprinids

• Ease of Breeding: Unknown - Captive breeding has only occurred accidentally to date.

Fish Diseases

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 stress these fish and make them prone to disease. Remember that any additions to a tank, such as new fish, plants, substrates, and decorations, can introduce disease. Properly clean or quarantine anything you want add to an established tank 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 dealt with 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 more closely their environment resembles their natural habitat, the less stress the fish will have, making them healthier and happier. A stressed fish is more likely to acquire disease. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.

Availability

The Chinese Algae Eater is very popular, moderately inexpensive, and readily available in pet stores and online.

References

• 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

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