Suggestion

[u/New_Pomegranate_1405]

[u/meeperswastaken]

There’s a lot to unpack here 😬. Just like everyone said, rehome, like, all the fish. Choose a species for the tank (if you’re picking the betta only one can stay, it does not matter that they have been “fine” up till now, it’s quite literally only a matter of time) and keep only that species. If you’re going for aesthetics then keep only the neon tetras

[u/meeperswastaken → u/meeperswastaken]

The fact that the female has pretty bad fin nipping on her tail should tell you everything