What are jellyfish doing in fresh water? They’ve appeared in Ohio, Pennsylvania

Your eyes aren’t deceiving you. There really are jellyfish in Lake Erie.

But what are jellyfish — most commonly seen in ocean water — doing in the Great Lakes?

These jellyfish are a little different. Craspedacusta sowerbii is a freshwater jellyfish species that is native to China’s Yangtze River, according to the National Park Service.

Though not as commonly seen in the United States, some have been spotted recently in Lake Erie.

The Pennsylvania Department of Environmental Protection said Ray Walter, a summer intern, captured footage of one of the creatures in late July in Presque Isle of Lake Erie in Pennsylvania.

“This tiny jellyfish is super hard to find. Most of the time, it’s stuck to the bottom as a little polyp,” the organization said. “But once in a while, it grows into the jellyfish shape we all recognize and Ray was in the right place at the right time to see it.”

The group called the sighting “incredibly rare,” a sentiment echoed by Ohio’s Stone Laboratory, which reported a sighting of its own.

The non-invasive jellyfish was seen at Stone Laboratory’s docks in Put-in-Bay, an island in Lake Erie, officials said Aug. 11.

Stone Laboratory research coordinator Justin Chaffin said it’s the first time he has seen one of the creatures in his 20 years doing research at the lake, according to WOIO.

But don’t worry, these freshwater jellyfish are harmless to people. Because they are so tiny — about the size of a penny — their stingers are not large enough to penetrate human skin, according to the National Park Service.

Craspedacusta sowerbii are “translucent with a whitish or greenish tinge,” the United States Geological Survey said. They have been 50 to 500 tentacles used for feeding or swimming.

According to the USGS, the jellyfish can be found across the U.S., especially in the Northeast region.