Freshwater jellyfish aren’t actually fish at all. They’re also not true jellyfish They are cnidarians, a group that also includes sea urchins and sea stars.
In their adult stage peach blossom jellyfish are typically only about the size of a penny, yet they can have as many as 500 tentacles total! But don’t be alarmed, they pose no danger to humans. Though they hunt for their food (mostly small insects and zooplankton) by using the stingers on their tentacles they are too small to sting larger organisms.
How did tiny jellyfish get into Illinois lakes? It’s likely they hitched a ride. Peach blossoms are native to the Yangtze River in China. It has been speculated that they came to Illinois along with imported aquatic ornamental plants. In fact, they’re world travelers that have now been spotted on every continent except Antarctica.
If you’re hoping to catch a glimpse, head to a southern Illinois lake in late summer for a great (jelly) fishing trip.