Just wanted to comment on the 14" max size. Mine is most definitely past that point.
I'd feel bad keeping him in anything less than his 125.
As for keeping dithers and other fish with them, I really think you're risking bloat when they're less than 5". I think it's best to grow them out solo. If you're trying to get a pair, try a group of 1 male:3 females, and expect 2 females to die of bloat or from being killed by a pair that forms and the strongest that bonds to the male to survive.
Once they're larger than 5", you can try some dithers or bottom dwellers. I've seen some do well, and others are killers. I had six 5" tin foil barbs, and every morning for 5 days, I awoke to a tfb that had been bitten in half. My habit doesn't like to eat tails for some reason...the last tfb in the tank is too smart for him, but he'd kill it if he could catch it.