If no inhabitants, then yes, you could heat up the tank. Paraguard or alum may be other options, as well.
The sources different on temperatures but just to be safe I'll probably try for 110F for a few hours unless that's a bad idea. I'm think I saw two little ones earlier so I know the bastards are in there.
Sorry to hear about the betta though.
Me too. I might be too inexperienced to keep fish. I lost three bettas in three years, despite having planted tanks with a filter, heater (78F), airstone, and light (on a timer). Lost one to anchor worms that were too tiny and white to see on his white body, another to internal parasites. It's a steep learning curve. Besides, they say bettas are the easiest fish to keep; if I can't even keep those alive, I shouldn't have fish.
I only had her seven months, and I'm starting to suspect she may have had internal parasites for a long time, and that maybe that is why she developed cataracts. She seemed so healthy, perky, and normal otherwise, up until a few days ago. I never saw her poop until more recently (when I noticed it was white and started treating her).
I don't think I'm going to get fish again, or if I do, not for a long time. And not a betta. Besides, I want to be sure any parasites or anchor worms starve to death in that tank. I'm not giving them another animal host. Will they turn on shrimp though, if I add them in a week? Or will turning up the heat also kill any possible anchor worms and parasites?
Edit: Oh shoot, my heater only goes up to 93 F--how do I get the tank hotter, do I put in a second heater? Then again all my heaters turn off when they reach their desired temperature; even if I put two of the same kind, they'll reach 93 F faster but likely not get higher than that. How the heck do I heat up this tank?