From Wikipedia, the free encyclopedia - View original article

Jump to: navigation, search
An adult "giant algae sucker", Pterygoplichthys pardalis
A young 'pleco' attached to the side of the aquarium glass

Hypostomus plecostomus (known colloquially as a sucker fish) is the Latin name for a type of freshwater tropical Central and South American fish belonging to the family Loricariidae. They are large algae eaters, and to differentiate them from small algae eaters, they are often referred to using the common names plecostomus, often abbreviated as plecos or plecs. Plecostomus is also a synonym of the genus Hypostomus and the genus Loricariichthys. They are extremely popular in aquariums for their ability to clean tanks by eating algae growth and dead fish. These friendly-natured fish can typically be purchased when about 8 cm (3.1 in) and often grow up to 60 cm (24 in). Such larger specimens are impractical for any but the largest aquariums.

Plecos are omnivorous, but in the wild feed nocturnally mostly on plant material. During the day, their unusual omega irises block a lot of light out of their eyes, but they are usually open at night. They can roll their eyes within their sockets, giving the appearance of winking. Plecos are usually skittish and quickly hide whenever they sense danger.


They are native to South America.[1]


A close up shot of a Common Plecostomus.

The name "plecostomus" means "folded mouth" (pleco, see pleat, stoma, mouth), but it has since been applied to any of a large number of species that have a similar shape, but vary widely in terms of maximum length, coloration, and certain body features such as the "horns" on the bristlenose catfish (genus Ancistrus).

Many types of suckermouth armoured catfishes remain undescribed. As a result, they are given a common name and an L-number designation until a new scientific name is agreed upon. An example is the flash plecostomus, L204, believed to be a species of Panaque.


Plecos are omnivores. They are not picky eaters. In planted aquariums, they will eat any food left behind by other fish, as well as naturally growing algae in the tank. They have also been known to have a taste for discus and angelfish mucus. In tanks without live plants, their diets can be supplemented with sinking fish food, usually algae wafers readily available from a pet store.

Although the plecostomus is a known common algae sucker, it requires more than just pellets and tank algae. It should also be fed algae wafers, zucchini, cucumber, lettuce, peas, and melon, and any semisoft fruit or vegetable will do, as well. They also can eat shrimp, shrimp pellets, and flake fish food.

Relation to humans[edit]

A maturing plecostomus sucking to an aquarium ornament

In aquaria[edit]

Plecos may become more aggressive with age and are best kept individually in tanks. Because of their potentially large size and aggressive behaviour, less aggressive catfish are preferable. In a suitably large tank, a solitary plecostomus will live amicably with other tropical fish. These catfish may survive in tanks with "cold-water" species like goldfish, but it is generally not advised due to the different temperature preferences and because some plecos will suck the protective slime coat off the goldfish. This, however, would indicate starvation. They are also able to withstand temporary interruptions in the aquarium air pump that would otherwise kill other types of fish.

A number of species are sold under the name common algae sucker, including Hypostomus plecostomus, Hypostomus punctatus, Pterygoplichthys multiradiatus, and Pterygoplichthys pardalis.

Plecostomus catfish are some of the most commonly kept algae-eating catfish, and are also some of the largest. Their growth may become stunted in a smaller tank, leading to bad health and possibly an early death. A 20-gallon tank or larger is necessary, depending on the species as some will grow 3", and some will grow 18" or more.[citation needed]


A maturing plecostomus sucking to an aquarium wall

Plecos, when introduced to an aquarium, will often find a permanent resting place (under or inside an ornament or rock, for example) to spend most of their time. This becomes a "home" for the plecostomus. If there are no hiding places, they will sleep in the corner of their tanks. Because of this behavior, it is advised that objects that they can get trapped in not be introduced into their environment.

Some fish keepers have trouble housing them in heavily planted aquariums because some plecostomus thrash their tails to develop a "well" in the gravel of the aquarium. It is often necessary to replant aquarium plants that they dislodge.

They can become aggressive if their hiding spots are taken by other hiding fish, such as brown knifefish, rope fish, and tire track eels.

Pool cleaning[edit]

In Florida, some people place plecos in the swimming pools of foreclosed homes. The fish can tolerate the poor water quality and control algae growth in the pools.[2]

See also[edit]


  1. ^ "Tank mates of Guppies". Retrieved 2010-02-16. 
  2. ^ "Florida Fish Called In For A Foreclosure Buffet". NPR. 2009-08-22. Retrieved 2013-11-25. 

Hobbyist clubs[edit]