Pineapple has a chemical in the core that does help with implantation, but you have to eat the core it's nasty,but worth it.
It is not for implantation, rather for increasing fertile cm. Pineapple and grapefruit both will help increase it.
i dont know about pineapple ...but i know that fish is not my ob told me to actually stay away from some types of fishes especially raw fishes like sushi!