Can a serpae tetra live with a betta crowntail in a 8 gallon tank. tetra is being harassed in 36 ga tank with other new tetra fish?

No, don't risk it. Serpae tetras are fin-nippers and they'll constantly stress out your Betta. Especially in a small tank such as an 8 gallon, I would find something else to go with the serpaes. (: