I've seen cases where "hasta" is used where, in English, we would say "not even", for example:
Even the cook didn't know how to cook the fish
Hasta el cocinero no sabia cocinar el pescado
But it seems like "siquiera" is more common:
Ni siquiera el cocinero no sabia cocinar...
But it's not quite clear to me if there are certain times when one is more preferred than the other. Anybody have any advice?