Rod's a girl clown.
If you get a smaller one you may have success
I don't think that really matters in this instance, since your moving them to such a large tank, but it is sage advice with clowns. Not only should the new clown be smaller than Rod, it should be the smallest (or one of the smallest) housed together at the LFS
. The reason is because clowns are wierd. They are all born neuter males, the largest most aggressive (or a solitary clown) in a clutch will change sex and become female, the next most largest and aggressive will become a functional male. The rest remain neuter males until one or both are removed, then the process starts over.