I have no idea, should i put my betta in the 30 gallon tank with the other fishes ( 3 Balloon Molly 2 Black Mollys and 1 white coloured molly which i think is a female. Would the betta attack the mollys or will the mollys nip the bettas long fin???
I've never tried it but it would concern me as mollies can be quite aggressive and betta's fins can be quite fragile. Also, bettas don't like salt and mollies thrive in salt. Bettas prefer soft, acid water; mollies like it fairly hard and alkaline.
I hear that Betta don't do well in very big tanks. I wouldn't try it with Mollies. It's very risky. You can try it and maybe you will get lucky. But if it doesn't work out, be sure to have a one gal tank ready for the Betta.