UPDATE
Well it was worth a try.
Left him for a week in q tank then I tried putting him in the main tank with the males and females as the girls had given birth by then.
He had a little go at the other males but was more interested in the females.
Maybe they were just sorting out the pecking order and I panicked too early.
Anyway pleased to say that they are all getting along fine now and haven't had to get rid of anyone.
Well it was worth a try.
Left him for a week in q tank then I tried putting him in the main tank with the males and females as the girls had given birth by then.
He had a little go at the other males but was more interested in the females.
Maybe they were just sorting out the pecking order and I panicked too early.
Anyway pleased to say that they are all getting along fine now and haven't had to get rid of anyone.