golden barb

Hello,how do i see if my golden barbs are pregnant? is it just fat or have eggs? it's bellies are a bit big,or they just grew bigger

I love to introduce Paroon shark & golden belly barb or golden tinfoil barb into my tank with Senegal Bichir inside.    Is it fine? The LFS here said it is gonna be ok. I just want to make sure first before buy it from you all guys.   What would be effect to my water condition like ammonia...