Pog: Their tanks were on daily 50-75% water changes after a full 100% change and scrubbing nine(?) days ago, so the water is very clean. They've also been given regular salt treatments for eight days to regrow their bitten fins, but obviously that's not the problem anymore... They are on API Stress Coat right now.
Olmpia: I will do just that, thank you. I have an incoming fish from AB and I would hate to see the same thing happen to him. ): Currently I'm using Tetra Lifeguard All-in-one-treatment because it was all I could find late last night. I'm down to my last $15 and I don't know if I can afford anything else.
... to me it sounds like either they have been poisoned (Spartan displayed the same irrational act, as did the guppies, he was the only survivor because I put him in a small bowl in clean tap water with conditioner!) or it could've been an internal bacterial problem, which can be contagious.