Landspeed Bottom Dwellers

Friday, October 25, 2024

Landspeed Bottom Dwellers

Today’s special animal friend is Hypostomus Plecostomus, the suckermouth catfish or common pleco.  We will call it the “pleco” for convenience.  The pleco belongs to the armored catfish family, Loricariidae.  This is the world’s largest family of catfish, with around 680 species in more than 90 genera.  Unlike the usual catfish in the United States, members of this family are covered with bony plates.  They are native to freshwater habitats in South America, Costa Rica, and Panama.

All Loricariidae species have a “suckermouth” with which they remove algae and detritus from rocks and other underwater surfaces.  They can also eat crustaceans and snails, abrading the shells away with odontodes or “dermal teeth,” hard extrusions of dentin and enamel near their mouths. They have adapted to breathe – that is, keep water flowing through their gills – while also slurping at slime.  Their digestive tracts are unusually long, allowing them to extract nutrients from vegetable matter, and they also have organs in their digestive system that allow them to breathe.  Because of this unusual feature, they can hop out of the water and go looking for more water.

Their very unusual motion, “involving their mouth, pectoral fins, pelvic fins, posterior axial body, and tail,” is unique to this fish family and is called “reffling.”  They are, according to the authors of a 2021 study of their motion, “among the fastest fishes on land,” which you wouldn’t think there would be many competitors.

Most of the armored catfish aren’t bothering us, but the pleco and some other species, including the vermiculated sailfin armored catfish, Pterygoplichthys disjunctivus, are wreaking havoc in waters of the southern United States.  They were introduced to the aquarium trade as “algae eaters,” little guys no bigger than your little finger that clean up your fish tank.  As so often happens, some were released into Florida waterways, where they bred and, freed from constraint, grew.  In addition to the usual invasive species annoyances – hogging resources, outcompeting native species – they attack endangered manatees.

But wait, there’s more!  Plecos like to mate and brood their eggs in burrows in the banks of lakes and streams.  Since they’re now the length of your arm and very numerous, this destroyes the banks, causing erosion, bank collapse, excess sediment, and the growth of toxic algae and cyanobacteria.

At least they have some predators: alligators eat them!

Other methods of control include electroshock, which stuns the fish, allowing Fish and Wildlife Service officers to pick up the invasive plecos and, I suppose, turn them into fertilizer, while leaving native fish to recover.

Here’s a vermiculated sailfin in Texas:

In the United States, invasive plecos and related species seem to be concentrated in Florida and Texas.  However, they are also a problem in other countries where people have dumped little aquarium algae eaters into bodies of water.  Unexpected!  (*drink*)