Query about Whatsapp Popup Notifications

I changed phones recently to a Android Nougat, and the issue I have with whatsapp notifications is that they tend to be very aggressive. Whatsapp notifications are the only ones that flash not just a notification in the notification bar on top but open the full message in the middle of the screen as soon as it is received. I am OK with notifications in the bar, but I don't appreciate a full message in the middle of the screen while I am working on something else or when someone else may be using my phone. Not only that, when it displays this, it marks the message as read which causes misunderstandings 'cause sometimes I just swipe it away without having read it 'cause i was busy with something else.

How do I turn this behavior off without turning notifications off altogether? I haven't received whatsapp messages today so unfortunately I have no screenshot. But I hope I was able to explain enough.

Thanks.