Famous question. Rabbi Yosef Karo in his commentary Bait Yosef (which would serve as a first draft of sorts of the Shulchan Aruch) writes not to eat fish with milk. His Ashkenazic counterpart Rabbi Moshe Isserles famously commented, "rabbi Karo mixed his milk with meat!", as the Talmudic quote regards fish with MEAT as being a health risk.

The fish-and-milk business was omitted from Rabbi Karo's later work, the Shulchan Aruch. So it's a question of how seriously we take the original comment in the Bait Yosef.

Non-Hassidic Ashkenazim simply follow Rabbi Isserles, that the whole statement was a mistake, and therefore there's no problem.

Among Sephardic Jews (who follow Rabbi Karo), and Hassidic Jews (who occasionally follow Rabbi Karo's stricter points), it varies from community to community. The mainstream Israeli "Eida Charedis" hechsher, which includes many Hassidic groups, will allow fish cooked in butter, but the Belz Hassidic hechsher won't. The Bukharian Sephardic practice may not be the Iraqi one, so you'd have to consult with your local hacham. Some rabbis also draw other differentiations, such as it's okay if they weren't cooked together (so yes bagel and lox, no tuna-noodle-casserole).

Here's more on the topic from Rabbi Brody in the Jerusalem Post.

Famous question. Rabbi Yosef Karo in his commentary Bait Yosef (which would serve as a first draft of sorts of the Shulchan Aruch) writes not to eat fish with milk (Yoreh De'ah 87:3). His Ashkenazic counterpart Rabbi Moshe Isserles famously commented, "rabbi Karo mixed his milk with meat!" (נראה שנתערב לרב בית יוסף בשר בחלב; Darkhei Moshe, ibid), as the Talmudic quote regards fish with MEAT as being a health risk.

The fish-and-milk business was omitted from Rabbi Karo's later work, the Shulchan Aruch. So it's a question of how seriously we take the original comment in the Bait Yosef.

Non-Hassidic Ashkenazim simply follow Rabbi Isserles, that the whole statement was a mistake, and therefore there's no problem.

Among Sephardic Jews (who follow Rabbi Karo), and Hassidic Jews (who occasionally follow Rabbi Karo's stricter points), it varies from community to community. The mainstream Israeli "Eida Charedis" hechsher, which includes many Hassidic groups, will allow fish cooked in butter, but the Belz Hassidic hechsher won't. The Bukharian Sephardic practice may not be the Iraqi one, so you'd have to consult with your local hacham. Some rabbis also draw other differentiations, such as it's okay if they weren't cooked together (so yes bagel and lox, no tuna-noodle-casserole).

Here's more on the topic from Rabbi Brody in the Jerusalem Post.

Famous question. Rabbi Yosef Karo in his commentary Bait Yosef (which would serve as a first draft of sorts of the Shulchan Aruch) writes not to eat fish with milk. His Ashkenazic counterpart Rabbi Moshe Isserles famously commented, "rabbi Karo mixed his milk with meat!", as the Talmudic quote regards fish with MEAT as being a health risk.

The fish-and-milk business was omitted from Rabbi Karo's later work, the Shulchan Aruch. So it's a question of how seriously we take the original comment in the Bait Yosef.

Non-Hassidic Ashkenazim simply follow Rabbi Isserles, that the whole statement was a mistake, and therefore there's no problem.

Among Sephardic Jews (who follow Rabbi Karo), and Hassidic Jews (who occasionally follow Rabbi Karo's stricter points), it varies from community to community. The mainstream Israeli "Eida Charedis" hechsher, which includes many Hassidic groups, will allow fish cooked in butter, but the Belz Hassidic hechsher won't. The Bukharian Sephardic practice may not be the Iraqi one, so you'd have to consult with your local hacham. Some rabbis also draw other differentiations, such as it's okay if they weren't cooked together (so yes bagel and lox, no tuna-noodle-casserole).

Famous question. Rabbi Yosef Karo in his commentary Bait Yosef (which would serve as a first draft of sorts of the Shulchan Aruch) writes not to eat fish with milk. His Ashkenazic counterpart Rabbi Moshe Isserles famously commented, "rabbi Karo mixed his milk with meat!", as the Talmudic quote regards fish with MEAT as being a health risk.

The fish-and-milk business was omitted from Rabbi Karo's later work, the Shulchan Aruch. So it's a question of how seriously we take the original comment in the Bait Yosef.

Non-Hassidic Ashkenazim simply follow Rabbi Isserles, that the whole statement was a mistake, and therefore there's no problem.

Among Sephardic Jews (who follow Rabbi Karo), and Hassidic Jews (who occasionally follow Rabbi Karo's stricter points), it varies from community to community. The mainstream Israeli "Eida Charedis" hechsher, which includes many Hassidic groups, will allow fish cooked in butter, but the Belz Hassidic hechsher won't. The Bukharian Sephardic practice may not be the Iraqi one, so you'd have to consult with your local hacham. Some rabbis also draw other differentiations, such as it's okay if they weren't cooked together (so yes bagel and lox, no tuna-noodle-casserole).

Here's more on the topic from Rabbi Brody in the Jerusalem Post.