I hate to say this, but consider it a blessing in disguise that the domino died. You wouldn't have had another fish live after having put him in there first.
The 90% water change may have set you back a little. That being said, the cycle is not in the water itself, it's in the rock and sand. Fish will do fine, and many corals as well, with 20ppm nitrates. Continue checking the nitrates - you may need some macro algae to help bring them down the rest of the way. When you start to add poopers, I would begin with some hermit crabs. There will probably be enough for them to munch on and clean while they further build your de-nitrating bacteria.
As for fish, if you love a clown pair, go for it. Prepare to be flamed and just take it with a grain of salt. You are very limited on the size and number of fish, but the great thing about clowns (and the one thing that makes them an exception in my book) is that they don't require a lot of swimming room. I've kept a pair in a 12g biocube, in a 45g, a 75g, and in my 225. It doesn't matter how much space is available to them, They never swim more than about 6" away from their 'home'. So, if this is what you like and want, pick out a small pair and give them something to 'hide' in. For the record, I wouldn't put an anemone in that small of a tank. Stay away from the larger (and more hostile) clowns like tomato. Also, it's probably best that you make that your only fish occupancy.
Good job so far.
