Well, these folks smuggle in these fish for healing rituals. But if the person they were smuggled in for gets well, they are obliged to release the live fish unharmed.
That is how they showed up in Maryland waters.
I guess it was only a matter of time before these world travelers brought to these shores the joys they left behind. Like polio, whooping cough, and other lovely things we had once protected ourselves from.
There is a cure for these snake fish and diseases, but we can't use it.

http://www.google.com/search?q=Snake+fish&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a