I would worry less about the bent spine than some other things here.
I just answered your question about the two cory catfish in your other thread, explaining how you must get more of them. Same applies to these two Serpae Tetra, but here you have another problem. This is a nasty fish, and prone to becoming even worse. They need a group of 10-12 in a 30 gallon tank as minimum. I would suggest you return the two Serpae quickly before they settle in and start showing their true nature, which will be even worse because there are only two of them. They could take it out on your cory catfish.