I have a Shi'a co-worker. Recently, our team planned a team lunch, and he mentioned that he doesn't eat fish, because of something called "kanta" (in Urdu). He said it's due to certain communities/nations in the past that were destroyed by Allah, and their people were turned into fish.
Can I get more information on this? I've heard only of Allah turning some people into swine and apes (which is mentioned in Surah Ma'idah). I would particularly like to know the evidences used by the Shi'a for this ruling, and especially if this is something widespread in Shi'a jurisprudence or exclusive only to certain sects/groups. And while not necessary, I would also be grateful for any information regarding how these same evidences are held among the Sunni schools of thought.