Wow, I can't believe no one has said bowfin yet. For freshwater I'd say bowfin or long nose gar. Saltwater I'd say rays.
I dont know why I didnt think of that! I was thinking like bass and panfish didnt even have bowfin pass my mind. But bowfin will absolutely destroy your light tackle. Ive seen one in person take some guys 15 pound line and snap it like its a hair. The bowfin started coming into shore and it saw us and it took off and instantly snapped his line. Also any carp will really bust up your rods and reels. If you hook into a 30 pound carp you could be there for a couple hours if youre using lighter tackle. Theres some carp near my house at the bashakill that are said to be over 60 pounds and some are easily over 1' wide and about 4' long. Biggest carp ive ever seen in my life. Id be scared to hook into one