if you're concerned about the fry, that no shark like will do, nor your neons and the livebearers itself for that matter. All fish will eat the newborn fry, in a heavily planted tank, you might be lucky and have some go in hiding untill they're big enough. But seeing as it's not unusual to have anything between 40 and 100 fry every 2 or 3 weeks (per fish), it wouldn't be good if all survived anyway
It would indeed be nice to know how big your tank is. Some sharks will have to be kept on their own completely, others can go in community tanks but not with their own kind, and others need to be kept in groups ... as you can see, its hard for us to advice you right now.