Yep, Pacifc Coast Co. aka “The Russian Costco.” Still worthwhile, but I assume it was the sanctions that led to fewer items directly from Russia. They still have plenty from the countries that used to be part of the USSR and Eastern Europe, but I used to see things like butter and milk imported from Russia. They also used to have the entire side room dedicated solely to Russian chocolates, but that too is gone.
And, yes, they do carry a lot of tinned fish (and jarred fish). Plenty of kvass and Russian sodas (taragon, buratino, pear) as well.