Well, I don't believe that moths are bad for a betta to eat, but it's bad for the water quality since the corpse can bring unwanted germs and such. The tank wasn't heated and I was upset with her for that as well. I'm glad that Miku is in her true home. However, I blame myself for the bad treatment that Miku got. I gave her away without truly looking into the family she was going to, so it was my fault. Miku has changed color from a dark green with stress stripes to a white body and colorful tail now that she's in a heated tank without an airstone or filter. The airsone, filter, and light broke down in the last tank, but a new one will be bought this weekend. The new one will be a 3.5 gallon tank, so she'll be a lot more happy and safe. I'm not sure if the color change is a good thing, but she's acting normal now that she's home, so I think it's a good thing. If it isn't then please, let me know.