For what it's worth... I say jump in with both feet and go salt!

I always put it off because I thought it would be much harder. It isn't and I find it more fascinating. (Still love a planted tank with fancy guppies, though!) If you want A fish (or maybe 2 really small ones), you can keep a nano-reef of 5-10 gallons; the only drawback to one that small is that, as with fresh water, the smaller the tank the quicker the water quality declines.

Good luck with your adventure!