Regarding dangerous to eat fish, Giant has in the past sold a fish called Basa or Pengas fish which is sheer ‘poison’. A friend had told me to buy this fish as it was a mild, inexpensive catch.
I asked the counter person where it came from and he did not know. I went home and looked it up on the internet, read disgusting and stomach turning description of what this fish was fed, that it was caught in the Mekong River (one of the filthiest rivers in the world), and I promptly returned the fish and told the Manager what I had learned.
Giant no longer carries this fish, but I would say to anyone buying fish to do your own research as you cannot depend on the FDA to protect us from poisonous food and poisonous food sources. They just don’t do their job.