Craspedacusta sowerbii (freshwater jellyfish)
 

Have you seen any freshwater jellyfish?
They are occasionally found in New Hampshire lakes and ponds.
For more information, visit New Hampshire Department of Environmental Services.

SpongeBob Lake Pants
 

There's a place down here where people see them while diving. Pretty cool.

In Winnipesaukee, however, there is an abundance of freshwater sponges. They aren't nearly as big or strong as the various saltwater varieties, but they are out there -- in colder water. I see them often.

Fresh water Jellyfish
 

That is really fascinating. One of my favorite books to read to my sixth grade students is a short science fiction called The Green Book by Jill Paton Walsh. In this book they land on a new planet to colonize and find the only other life is fresh water jellyfish; which they end up using as fuel. :)

good idea
 

How many miles-per-gallon can we expect if we start harvesting these?