What do I do about my injured bleeding heart tetras?

I'm not exactly sure how they go injured because they were bought that way but the ends of the fins are almost all gone. I don't know what to do about it so what can I do? They seem like they are struggling to swim. I really don't want to add any medication because I don't want to take out the filter media. So what can I do? Also one of the tetras doesn't have the heart thing on him, will it start to appear as the tetra gets older or is that how it will be all of its life? If it matters only 2 of the tetras have the injured fins.