Water boatmen

Corixidae · Aquatic life

Whole animal · Photo: Doug Macaulay / CC BY

NativeAquatic insect

Also called Corixids, Boatmen

How to identify Water boatmen

Small oval bugs about 1/8 to 1/2 inch
Swim right side up with a flat, finely striped brownish back
Long oarlike hind legs fringed with hairs
Short scooplike front legs
Carry a silvery air bubble and often cling to the bottom or plants

Similar species

Backswimmers swim upside down, have a keel shaped pale back and can bite. Water boatmen swim right side up and are harmless.

Profile

Season	Active spring through fall and often seen under the ice in winter; big flights in late summer and fall.
Starts	Active even in cold water
Depth	Shallow water near the bottom and plants
How it spreads or reproduces	Adults fly between waters and are attracted to lights and shiny surfaces
Habitat	Ponds, lakes, canals, lagoons and even salty or alkaline water; often abundant in new or fishless ponds and swimming pools.

Why it matters in a lake

Mostly harmless feeders on algae and detritus, though some species also eat midge larvae and other small animals; they cannot bite people the way backswimmers can. A major food for fish and waterfowl, and large numbers often show up in fishless ponds, pools and new water features.