I pretty much stick with livebearers, that includes lots of the less common ones like the goodeids and very few of the pet shop type. I also enjoy small fish in general so I keep all 3 species of pygmy cories. Like inchworm, I am discovering that cories can make a tank come to life all by themselves. Right at this moment I have some rainbow cichlids that just keep breeding and I have actually decided to save a few from their last spawn. They will be my first egg layer fry in about 40 years so you could say that I specialize in livebearers.