Suckermouth Catfish: Species Profile

Suckermouth catfish resting on gravel

DEA / Getty Images 

Suckermouth catfish is the common name for members of the Loricariidae family of catfish. It includes 92 genera and over 680 species, only of a few of which are common in the pet hobby. Also known as a plecostomous or pleco, these fish are common in tropical community fish tanks. They are characterized by their mouths that are used to suction themselves to rocks, wood or the sides of your aquarium.

Species Overview

Common Name(s): Suckermouth Catfish, Plecostomous, Pleco

Scientific Name: Hypostomous plecostomous

Adult Size: 3 inches to 2 feet

Life Expectancy: 10 to 15 years

Family Loricariidae
Origin South America
Social Peaceful
Tank Level Bottom dweller
Minimum Tank Size 125 gallons
Diet Herbivorous omnivore
Breeding Egg layer
Care Beginner
pH 6.5-7.5
Hardness 5-10 dgH
Temperature 72 to 82 F (22 to 28 C)

Origin and Distribution

Native to the rivers of South America, the suckermouth catfish is only one member of the plentiful Loricariidae family. Also known as Pleco Hypostomous or "Plecostomous," these fish have been captive-bred for many generations. They are an invasive species within the Americas, Asia and Europe.

Colors and Markings

Suckermouth catfish are known for their scales or bony plates that look like armor. These dense scales may have extra ridges that give the fish a spiky appearance. The suckermouth catfish is mainly brown in coloration with darker spots and/or stripes. Some fish may have tan or yellow patterns. This excellent camouflage makes them difficult to see in heavily planted tanks.

The suckermouth catfish is named for their specialized oral cavity. Their raspy mouthparts are specially designed to grind up plant materials and have evolved to allow the fish to breathe while staying suctioned to a flat surface.

Close up of suckermouth catfish mouth
slowmotiongli/Getty Images 

The Loricarridae family have a unique feature of their eyes that allows them to see well in many different water environments. Instead of a traditional iris, they have an omega iris, which is a dorsal fold of their iris extending into the anterior chamber of the eye. By moving this up and down, they control how much light enters their eye, allowing them excellent vision in both brighter and darker water.

Plecostomous with omega iris
 Juan Daniel Pineda Jimenez / Getty Images


Being mainly herbivorous and a peaceful fish, the suckermouth catfish gets along with many other community players. Even when they reach their maximum size, around a foot or two, they will leave other fish in the tank alone. Some good tank mates include smaller fish, such as platys or neon tetras, or larger tropical fish such as rainbowfish or congo tetras. You may add multiple Loricariids to one tank, but keep in mind how many gallons each fish will need!

Despite some online postings, the suckermouth catfish and its various plecostomous cousins are not well suited to outdoor ponds. These fish require a smaller range of water temperatures than most ponds can supply. If your pond is heated year round, as long as you have temperature checks in place, you may consider moving larger suckermouth catfish to your pond.

Suckermouth Catfish Habitat and Care

The biggest consideration when keeping a suckermouth catfish is having enough room for your fish when they reach full size. Although they start very small, you will need at least 125 gallons per fish.

Many tanks with suckermouth catfish are heavily planted with lots of natural woods for the fish to nibble upon. Whenever you are adding wood to a fish tank, be sure it is a species of wood that will not leach any toxic substances, such as eucalyptus, and has been thoroughly cleaned. Once you have a good piece of safe wood, allow it to soak in chlorinated water for at least 24 hours. Rinse it thoroughly before adding it to your aquarium. You can skip this step by only purchasing woods made specifically for aquariums, but always rinse them first to remove dust.

Suckermouth Catfish Diet and Feeding

Although mainly herbivorous, like all other fish, the suckermouth catfish needs to have a well-rounded diet and cannot subsist on the algae in your tank alone. Many herbivorous fish pellets are available with a flat disc shape ideal for suckermouth catfish. The suckermouth catfish does well on a mix of herbivorous/omnivorous foods and like a wide variety of commercially available tropical fish diets.

Supplementing with vegetables is an enjoyable task when keeping suckermouth catfish. There are a variety of fresh vegetables you may add to your tank for the benefit of all your fish, not just your suckermouth catfish. Again, this should not be the bulk of their diet, but an occasional supplement. Most of their nutrition should come from their pellets.

Gender Differences

Unlike other varieties of plecostomous, the suckermouth catfish does not have any distinct external features to determine males vs. females. As with many other species of fish, female suckermouth catfish tend to have larger, rounder bellies, whereas the males tend to be slender and skinny. However, this may be hard to determine without two fish of the same age and care. Underfed or sick females will easily resemble males.

Breeding the Suckermouth Catfish

Once you have a male and female in the same system, the suckermouth catfish likes to spawn on smooth rocks and divots in your substrate. This will often occur in a quiet corner of the aquarium that is not easily accessible. Females will lay the eggs and males will externally fertilize the eggs within the new nest. Males will remain to guard the nest until the fry hatch.

More Pet Fish Species and Further Research

If you like suckermouth catfish, or are looking for potential tankmates, read up on:

Check out additional fish species profiles for more information on other freshwater fish.