He ruled a few weeks ago that most fish were not kosher because they had worms in them.
There have always been worms in fish, Rashi says so in his commentary on the Talmud, the question was always which ones are allowed and which ones are prohibited. Are there worms in this fish or not? To talk about all fish this way is silly.
Rabbi Gadol emails: If more Torah Juden resolved to follow a proper Seventh Day Adventist diet (like Luke), there would be no need for Jews to vex themselves with invidious discussions of parasites in fish. It is only a matter of time before we learn that there are insect parasites in fleish (beef), if not through infection than through abiogenesis. Hence, to truly avoid the problem, one must avoid all fish, beef, chicken and so forth.
Of course, that does not mean that Yidden are free to eat strawberries or other goyishe fruits known to harbor insects! We can not be as a “light unto the nations of the world” if we eat the cousins of the firefly.
Similarly, I must posek that it is forbidden for a Jew to ride a bicycle at any time and at any place when there are flying insects about. It is inevitable that while riding a bicycle, one has one’s mouth open, in which case it is just a matter of time before one swallows an insect. This is, of course, assur. Some posek that one may ride a bicycle provided one is wearing a face mask to keep the insects out even when one’s mouth is open. but this strikes me as insufficiently high a fence around the Torah. And remember: oral law comes from G-d on Mt. Sinai.