I’ve been asked, what is the deal where many Sephardim will not eat fish with dairy.
Here is the story:
The source of the discussion is the Beit Yosef in Yoreh Deah 87, where the printed text says:
“ומ״מ אין לאכול דגים בחלב מפני הסכנה”
But virtually all the evidence shows this was simply a printing mistake.
The Beit Yosef himself, in the Shulchan Aruch, explicitly permits fish with dairy.
And the Rama already writes that the Beit Yosef clearly mixed up “fish with meat” and “fish with milk.” The Beit Yosef even cites Orach Chaim 173 as his source — and over there the discussion is about fish and meat, not dairy.
So the entire issue originates from a mistaken line in a printed text, not from an actual halachic position of Maran. Even the Ben Ish Chai says it is not an issue
Some later Sephardic authorities, including Chacham Ovadia Yosef, felt that since certain Sephardic communities adopted the practice, it should be respected as minhag. But my understanding; and my father was very firm about this; is that a minhag that developed from a clear printing error does not become binding minhag. Especially when the author himself explicitly ruled the opposite in Shulchan Aruch.
Therefore there is no issue at all with eating fish and dairy together.