If your looking for personality then I would start with SA/CA cichlids, specifically the larger species. With a tank size of at least 75g for a single specimen like oscars, jaguars, trimacs, black belts, or festae. When a fish is kept solitary it's entire world is you, when pairs are kept the attentions dwindles since they have constant company. I have all of the above mentioned fish except for black belts, and each one from inch on shows distinct character traits. For a pair of any of these big boys a 125g or larger will be required since the biggest trait is aggression, it's not uncommon when a fish reaches maturity or when mating begins to kill the opposite fish. These are fish that can switch to insane at a moments notice so be prepared to divide or separate them quickly. So if you have the room theres no better fish to create that "wet pet" than one of beasts from down south. It's funny after owning these guys for a number of years and reading different forums about "my tiger barbs are nippy" they have no idea what a nipping is until they see a 16" jag seeing another fish they don't like. Good luck with your decisions.