Hi,
"Today
there are also those who are careful to have fish in every Shabbat meal; this
has a hidden reason."
(Rabbi Yechiel Michel Epstein, Aruch haShulchan Orach Chaim 242:43)
Is Rabbi Epstein referring to the way fish procreate prolifically? Or to their immunity to the ayin hara of others' jealousy? I suspect not, since both of those are well-documented in Jewish tradition. I don't know what the secret here could be.
Have a great day,
Mordechai