As an American stumbling in here from /all with no German language skills, Google says:

1: What are you currently doing? 2: I’m studying dual. 1: Did you just call me [an] eel?

From what I can gather in a minute of attempted research, there is a pun that is lost in translation.

Otherwise haha yes eel very good (someone call security and have these gentlemen escorted out, they are speaking nonsense).