Widowed Percula Clown

[Delphinus]

Essentially what you want is a tiny one, he will be terrified into submission and thus staying male. There will be fireworks, but basically the bigger the size difference, the faster it will end. Ie., it sounds mean to get a little one so that he'll be scared but once he accepts that he's the male, it should become a pairing again (I've done this and it worked out). If you get one close to the same size, there may be more aggression as they try to fight out who gets to be dominant.