Yes I think so too, I just gave her a burial in a tissue paper in the trash bin unfortunately. Had them since june 9 in a 10 gal with about a 20% wc a week. I just upped the heat and added AQ salt in home tank and just did the weekly clean as well.
Tomorrow I'll go out and acclimate a new betta to ensure the 3 in my tank don't harm each other. I also plan on getting either a 4th oto or a 5th betta as well as a couple more plants since 2 I got from petco aren't true aquatics and their lifespan in my tank has worn out.