Willy Dibbert

As a general rule, most fish diseases will not affect crustaceans, and most diseases that affect crustaceans will not affect fish. If your Killifis fish is large in size it is an interesting combination as it is one of the friends that are said to live peacefully with crayfish.

Although female bettas are not as common as males, they can do well in community aquariums. But provided that the tank has a capacity of more than 10 gallons. Because if your Betta lives in less of an environment, it won't be able to tolerate other fish, whatever they are. And although they don't fight like males, they can still be aggressive at times. If she's a decent person and nothing has happened, you probably don't need to move her out.

Maybe not, cause salt is not well tolerated by plecos long term due to them being scaleless