Plecostomus
The Plecostomus, Pleco, or Plec is a general name for a type of freshwater tropical Central and South American fish belonging to the suckermouth catfish family (Loricariidae). The name is derived from the species known as the suckermouth catfish (Hypostomus plecostomus), however, 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. Plecos are extremely popular in aquaria for their ability to clean tanks by eating algae growth, however they are often very poor at doing this. These fish are typically sold at about 3 inches and may grow up to 1-2 feet depending on species.
Plecostomus are omnivorous but, in the wild, feed mostly on plant material at night. During the day, their unusual omega irises block a lot of the light out of their eyes. The iris opens at night. Plecos can also wink using an eye membrane.
As they age, plecostomus can become more territorial and are best kept individually in tanks. Because of their large size and territorial behaviour, when stocking smaller aquaria it is often better to consider a bristlenose catfish, which generally grow to about 6", are very peaceable, and also eat algae. In a suitably large tank a solitary plecostomus will live amicably enough in a community tank alongside other tropical fishes. Because they are tropical fish, these catfish cannot be kept in coldwater tanks with things like goldfish.
There are a number of species that are sold on the market under the name Common Pleco, including Hypostomus plecostomus, Hypostomus punctatus, Liposarcus multiradiatus, and Liposarcus pardalis.
There are many other types of suckermouth catfish that science has not described. As a result, they are given a common name and an L-number designation until a new scientific name for the fish is described. An example is the Flash Plecostomus, L204, believed to be a species of Panaque.
External Links
http://www.planetcatfish.com/shanesworld/175.PHP A discussion of why all Loricariidae have come to be called 'plecos' - originally published in Tropical Fish Hobbyist, June 1999 .