Hypostomus plecostomus, also known as the suckermouth catfish or common pleco, is a tropical freshwater fish belonging to the armored catfish family (Loricariidae), named for the longitudinal rows of armor-like scutes that cover the upper parts of the head and body (the lower surface of head and abdomen is naked soft skin). Although the name Hypostomus plecostomus is often used to refer to common plecostomus sold in aquarium shops, most are actually members of other genera

Suckermouth catfish are of little or no value as a food fish, although they are at least occasionally consumed over their native range.a demand exists for them, however, as a bottom cleaner in the aquarium trade.

H. plecostomus is one of a number of species commonly referred to as “plecostomus” or “common pleco” by aquarists. These fish are sold when they are young and small, but in the wild, they can grow to be a maximum size of 50 centimetres (20 in).In captivity, however, a full-grown Hypostomus plecostomus only reaches 15 inches (38 cm) on average, which could be explained by the subpar oxygen levels in most home aquaria and other practices of bad fish husbandry. In the aquarium trade, this dark-colored, bottom-feeding, nocturnal catfish is often purchased for its ability to clean algae from fish tanks but also contributes a lot of waste to the nitrogen cycle. They are difficult for other fish to harass, both due to the semi-aggressive nature of the fish as well as its thick armor.

size (2″- 3″)