wrong! American eels aren't amphibians, they're fish. They start out as saltwater fish that are born somewhere near the West Indies. They travel in ocean currents, and grow & mature in salt water. Some spend their entire lives in saltwater or brackish mixes. They like flowing water (streams), and can reach 3-5 feet. They're carnivores, but mostly scavenge. Every once in a while people catch them here in Western Pennsylvania when they're trying to catch catfish.
Other than that, I don't really know anything about them. I'd guess that like most NA natives they're gonna need cool temps & really clean water. Dunno if they'll live forever in freshwater or if you'll have to move them to salt.