Dear WW: Not a really good example, but the lamprey eel
and the true (Sargasso?) eels look quite similar except for
mouth parts.

Here's a URL with a lot of pictures of fish found in Pennsylvania:
http://216.239.53.104/search?q=cache:qDo3fZN4SbsJ:sites.state.pa.us/PA_Exec/Fish_Boat/pafish/fishhtms/chapindx.htm+picture+lamprey+eel&hl=en&ie=UTF-8

Sorry that URL made screen go wide.