### Barbronia weberi (Asian Freshwater Leech)
Identification
Don’t let its "worm-like" appearance fool you; *Barbronia weberi* is a sophisticated, lithe predator. Measuring a modest 25–40 mm when extended, this leech is characterized by its slender, cylindrical body and a color palette ranging from a vibrant, translucent rust-red to a dark, muddy chocolate. The definitive field mark is its eye arrangement: look closely with a hand lens to find three distinct pairs of eyes—one pair situated anteriorly at the very tip, and two pairs tucked slightly back on the sides of the "head." Unlike the flattened medicinal leeches, *B. weberi* is nearly round in cross-section and lacks a distinct "neck."
Habitat & Range
Originally a resident of Southeast Asia’s warm, slow-moving streams and rice paddies, this species has become a world-class traveler. Due to the international aquarium trade, it is now an invasive "hitchhiker" found in ponds and drainage ditches across Europe, Australia, and the Americas. It thrives in nutrient-rich, stagnant, or slow-flowing freshwater, often hiding among the roots of floating vegetation or under submerged stones.
Behaviour
An observer at the water’s edge will likely see *B. weberi* performing its signature "looping" crawl—anchoring its posterior sucker, stretching its body to incredible lengths, and then snapping its rear forward like an inchworm. It is primarily nocturnal, spending the daylight hours tucked into crevices to avoid desiccation and predators. It is also a surprisingly capable swimmer, moving through the water column with a graceful, serpentine undulation.
Diet
This is a predator, not a parasite. *B. weberi* does not seek mammalian blood; instead, it is a terror to small invertebrates. It actively hunts oligochaete worms, snail larvae, and chironomids (midge larvae). Using a muscular, toothless pharynx, it creates a vacuum to swallow its prey whole or suck out the soft internal tissues of its victims.
Fascinating Fact
This leech practices a bizarre form of "traumatic insemination." During mating, one leech will press a sharp packet of sperm (a spermatophore) against the body wall of another with such force that it pierces the skin, allowing the sperm to swim through the body cavity to reach the eggs!