Supplement (Omega-3 Fish Oil)

Hi! I’m a 27F and 3-week pregnant. I’ve been reading articles online on what supplements to take. Many articles recommended Omega-3 Fish Oil. So I would like to check with y’all, which brand of Omega-3 Fish oil have y’all been taking? Should I be concerned about the mercury level in those supplements? If yes, How do you check the mercury level? #worried #firs1stimemom #firstmom