Suckermouth Catfish
An armored, bottom-dwelling catfish from northeastern South America that's turned up across the southern US through aquarium releases, with the only confirmed reproducing populations holding in central Texas spring systems.
Anglers know it as the pleco — a prehistoric-looking fish that grazes algae and detritus from rocks at night. Most plecos encountered in Florida canals are actually closely related Pterygoplichthys species, not true H. plecostomus.
Scientific Name: Hypostomus plecostomus
Also known as Common Pleco, Pleco, Plecostomus, Algae Eater, Janitor Fish, Armored Catfish
- Body sheathed in rows of bony armor plates (scutes) along the head and back, with a soft, naked belly. Coloration is mottled brown to sandy with dark spots that vary by water.
- The giveaway is the underslung, sucker-like disc mouth used to rasp algae and scrape food from hard surfaces, paired with small high-set eyes that pinch shut in bright light.
- Pectoral fins carry thick, toothed spines — strong enough to hold the fish against current and capable of puncturing skin during handling.
- True H. plecostomus is shorter and stouter with under 10 dorsal fin rays; the larger sailfin-type plecos common in Florida (Pterygoplichthys) carry more than 10 rays and a tall, sail-like dorsal.
What to know
Habitat Distribution
- Non-native everywhere in the US. Confirmed reproducing populations of true H. plecostomus exist only in central Texas spring-fed systems where year-round warm water makes overwintering possible.
- Isolated specimens have turned up in Florida, Hawaii, Nevada, Puerto Rico, and a handful of other states — almost all traced to aquarium dumps, with no self-sustaining populations outside thermally stable waters.
- A tropical species at heart: prefers 72–86°F water and tolerates pH from roughly 6.2 to 8.2. A modified stomach lets it gulp atmospheric air, so it persists in low-oxygen canals, ditches, and bayous that would suffocate most fish.
- Found in slow-moving rivers, spring runs, urban canals, and drainage ditches — generally avoiding truly stagnant water but tolerating murky, mud-bottomed, lightly flowing systems.
Specific Spots
- Hugs the bottom along shorelines and shallow flats wherever rock, driftwood, or hard substrate grows a film of algae worth grazing.
- Tucks into bank burrows, crevices, undercut rocks, and woody debris during the day — these same burrows double as spawning chambers and can riddle a stream bank.
- Anchors to rocks and logs in moderate current using its sucker mouth and pectoral spines, holding station in flows that would push other bottom fish off.
- Nocturnal by habit: at night the fish move out of cover to feed across exposed substrate, which is when incidental hookups happen.
Suckermouth Catfish FAQ
Answers from onWater's species guide.
What are the best lures and bait for Suckermouth Catfish?
Bottom baits at night are the only reliable approach: dead minnows, worms, crickets, and cut bait fished still and tight to the substrate where the fish are grazing.
What do Suckermouth Catfish eat?
Mostly a detritivore in US waters, research on Texas spring populations shows decaying organic matter dominates the gut, with algae and plankton playing a smaller role than the "algae eater" nickname suggests.
Where do Suckermouth Catfish live?
Non-native everywhere in the US. Confirmed reproducing populations of true H. plecostomus exist only in central Texas spring-fed systems where year-round warm water makes overwintering possible.
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