In Lake Michigan, USA. Photo generously provided by David Barnes, Purdue University.
Pectinatella magnifica is a fresh- water species,
Original description: Cristatella magnifica Leidy, 1851
Another image - courtesy of Wayne Campbell, Hila Science Camp, Canada.
"Moss Animals invade Lake Cochituate" - an account of the sudden appearance of Pectinatella magnifica in a lake in Massachusetts, by Dick Miller.
Pectinatella magnifica page at Freshwater Bryozoans in the Netherlands (Michiel van der Waaij).