My first experience with saltwater fish was actually breeding. I was part of a laboratory group that bred Percula and Ocellaris clownfish. It was tough at first, but I worked with some very experienced people, and we went all out. It definitely helped me learn everything quickly. When I started keeping saltwater fish in my personal home, it was a piece of cake. We didn't do any selective breeding though. We did get some interesting misbar patterns, and some hemibranchs as well. We also briefly forayed into dottybacks and watchman gobies. We had a pair of Indigo (sankeyi x fridamani), but we never were able to successfully rear larvae. We did get some watchman goby babies though. The problem there was pairing them up. We would get dominant individuals that would rather kill than pair. Eventually we got some to pair though, and it was really cool to watch.
In my personal time, 6 years later, I breed and have bred swordtails (I have a rather nice pair of pure swordtails, in their natural color, with no mixing of platy genes), mollies, platies, firemouth cichilds (raising some babies now, that are officially big enough to be on frozen mysis shrimp), convict cichlids, and guppies. Future projects include Hippocampus erectus (I have two females now, as I don't have a tank to rear the fry yet) and maybe green banded gobies.