Betta Fish: Got a free fish today

I try to avoid Petco at all costs as a general rule, but today a heater stopped working, so off to the hive of villainy I went. And there he was, actively dying on the bottom of his cup. I hate the manager of my store. He's a compassionless hobgoblin, and they always have a wall of dying fish freezing next to the doors. Anyway. I argued with him until he gave me a free fish. He is in bad shape, but he's in clean, warm water and I am hoping I got to him in time. I'm not going to name him just yet. If he lives, he'll have me and 9 betta siblings as his family. (Dont panic, they all have their own 10g tanks. Expensive assholes.)