Finally – a thread we can all really sink our teeth into!
So here is my question: Do fish ever reproduce on their own with other types of fish, i.e can a flounder spawn with a non-kosher species of fish, in the ocean? If so, how would we ever know what DNA was in the fish, if the fins and scales were present? Hashem said fins and scales determine the kashrus of the fish, so it would SEEM that if those are both present, the fish appears to be kosher. If Hashem had just named kosher fish in the Torah, without defining the simanim, it would be a different issue. I wonder what the rabbanim say.