The Water Penny larva is a remarkably flattened, oval, copper-brown beetle larva that adheres to rock surfaces in fast streams, looking exactly like a small, round penny. Its flat shape reduces drag in strong current and allows it to scrape algae from rock surfaces. When conditions are right, adults emerge as small brown beetles and live briefly near streams.
Best time to see a Water Penny
The best time to see a Water Penny is March–July, when about 64% of U.S. sightings happen, based on 1,798 research-grade iNaturalist observations.
Not certain it is a Water Penny? What bug is this? walks through what to check first and the lookalikes that catch people out.
Recent Water Penny sightings near you
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