Betta splendens in new tank.?

hi i have had a male betta for 3 weeks now, he has been in a 12 litre tank, and yesterday i bought a 150 litre tank that i am going to put him in with some tetra's, some ghost shrimp and maybe some mollies( i havent made my mind up yet). i was wondering if i could put 3 female betta's with him? and also because he has been alone will he get scared/threatened by them? thanks.