How much tuna is considered harmful?

Jaxonsmomma2012

I'm craving tuna right now (one of the only cravings I've had while pregnant has actually been for fish fillets from McDonalds and tuna..) .. How much is too much to eat at one time? While my mom was pregnant she would eat 2 cans at a time 3x a day every single day and I turned out fine.. But I'm just wondering how much is considered safe by doctors and such.