The biographical encyclopedia of Ibn Khallikan–that deep well of collective anecdotal wisdom–has an interesting entry for one Abu Al-Abbas Muhammad Ibn Sabih.  His surname was Al Mazkur, but like many famous figures it is his nickname that posterity recalls best.  This nickname is Ibn Al-Sammak, which literally means “son of a fish-monger” in Arabic (the word for fish is samak, سمك).  It is not clear where this name came from; perhaps he had a fish-merchant as an ancestor.