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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

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.


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.

Pool cleaning[edit]

In Florida, some people place plecos in the swimming pools of foreclosed homes.[citation needed]

See also[edit]


  1. ^ "Tank mates of Guppies". Retrieved 2010-02-16. 

Hobbyist clubs[edit]