[Avodah] fish and milk

[saulweinreb at Comcast.net]

 R' Zev Sero writes:

"In practise, most Sefardim seem to follow this BY, at least to some
extent, while among Ashkenazim AFAIK only some Chasidim do so.  I
speculate that the Chasidim copied this practise from Sefardim,
along with many other practises."

When I was learning in Kollel in EY, I had a chavrusa who was a sephardi.  We were learning that siman in shulchan that deals with the BY's alleged mistake re: fish and milk.  My wife called me to invite my chavrusa for dinner that night, because she had to go out and we needed to learn at home for night seder so we can be with our baby until she could get back.  He had no problem with the arrangement, and gladly accepted our invitation.  Needless to say, my wife made a tuna casserole that night and much to her chagrine, our guest could not eat with us.  My wife thought at first that this Israeli born sephardi had obviously never seen tuna casserole before, and she tried to encourage him to try some.  He had to tell her that sephardim won't eat fish and cheese together. We still think of my chavrusa every time we have a tuna casserole for dinner.
  
On a more serious note, if we accept the DM that it is a mistake, obviously we do not need to be machmir on fish and milk.  But even if we accept the mefarshim who explain that it was a seperate sakana, why do we have to be machmir if we now do not know of any sakana? The debate about meat and fish is well known, that we are machmir even though current science doesn't identify any health risks with meat and fish together, but that is because it has become accepted as an issur in klal yisrael. it is hard to believe that we could apply the same rules to fish and milk, which most people do not accept as dangerous AND medical science has not identified any such danger?