Eels?

American Eel I Caught Last Year

You think American eels are thin? Check THIS sucker out, I caught it in a pond on the RI/CT border last year. Easily 4+ pounds and bigger around than a beer bottle. Nasty bugger, holy slime coat!

They are truly anadromous (sp?) fish they migrate from fresh to salt water to spawn, but when they become landlocked they become ferocious predators, I have heard about them reaching 6 feet in length!

 
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