I used to love tuna, Sainsbury's tinned skipjack tuna steak in sunflower oil, no other kind.
One night I saw a tv programme on fish hosts and it showed a whole dead tuna with live wriggly things with faces, stuck to it's 'mouth' as they cleaned it.
A few weeks later in MailOnline, I read about a woman who'd bought tinned tuna and on opening it, saw one of those same wriggly things on the top. There were photos and I've never bought tuna since.
That means thst I only have cod or possibly haddock but even those have worms. Now I just eat fruit, veg, pulses, dairy, pasta, rice and breads but I make my own.