Plecostomus or "plecos" refers to both a specific species of freshwater catfish commonly seen in the pet trade and to a group of freshwater catfish that share similar body structures and habits. All of these species originally are from South or Central America. In captivity, plecostomus live at the bottom or sides of tanks, cleaning algae off decorations and walls. Although their main diet is algae, they need a variety of fish foods to remain healthy.
Also called suckermouth catfish or Hypostomus plecostomus, this is the most readily available and the largest, growing up to 24 inches, according to "Complete Encyclopedia of the Freshwater Aquarium." Pet stores often sell small babies and neglect to inform customers just how large these fish can get. Their colours are a mottled brown, albino and piebald or a black and white. They are good in ponds and living with large cichlids.
These are a smaller plecostomus species with brilliant stripes or spots. The species includes the spotted pleco or Hypostamus punctatus, which grows to 12 inches and the zebra pleco or Hypancistrus zebra. Royal plecos resemble zebra plecos, but are not as vividly striped. The snowball or snow king pleco sports a dark brown body with brilliant white spots and grows to 15 inches long. The golden nugget or golden seam pleco also sports a dark coat, but has brilliant yellow spots and edging along the fins and usually does not grow more than 14 inches long.
About 12 species do not grow past 6 inches long, according to "Complete Encyclopedia of the Freshwater Aquarium." The candy-striped pleco or Peckolito vittata is banded in yellow and brown and grows to about 4 inches. Bristlenose plecostomus or alligator plecostomus appear in a variety of colours and fin lengths but rarely grow more than 4 inches long. As their common name suggests, they sport many branches at the end of their noses. The "bush" is merely many short barbells or "whiskers."
These types of plecostumus catfish are rarely available in pet stores but may be available through individual breeders or at local fish shows. They are colour variations of other species as well as species new to freshwater aquarists. Rare types include whiptails, which have very long, thin tails. The green phantom pleco is green-brown with yellow edging on the fin-tips and some yellow spotting. Tiger plecos are striped like zebra plecos but in black and orange or yellow. The vampire plecostomus or Leporacanthicus galaxies is named for its long mouth parts which look like fangs.