Hello,
Welcome to the hobby, its fun here! The first thing to figure out is are you going for a reef or a fish only with live rock setup. If you go FOWLR, you have more options on fish. If you go reef, you have endless coral options, but it impacts the fish species you can choose. I have to agree completely that a 40 gallon breeder or a 65 are the best choices for a first tank. Smaller tanks are definately harder to maintain, and the 18 inch width is a very good thing. The only thing I would use a 55 gallon tank for in this hobby is as a sump. Furthermore, I believe 55's are all tempered glass and cant be drilled. The big issue with a 55 is the 12 inch width. You often need wide pieces of live rock at the base of you aquascaping, and you will find 12 inches is really cramped. I would personally go with the 65, but having said that, my first tank was a 40B. It was a nice start, no sump, and my corals did okay. When I transfered everything to my current 90+40 sump, everything took off. The oxygenation offered by using a sump is important, plus it gives you a place to dose things or add top off water without dosing or topping off right on your corals. If you do decide to go reef, these concepts are very important for consistency.
As for your fish choices, everything looks pretty good. Some points on the species you discussed. First off, there is no such thing as a black percula. I say this due to frustration with one of my lfs, they mark their black ocellaris as black perculas. Black ocellaris clownfish are excellent beginner clowns, and very beautiful, even the most common patterns are awesome. When I got into marine fish, I loved how they reminded me of miniture killer whales. Might sound weird, but hey, we all have our little ideocincricies. Get a young pair, about the same size, and they will most likely develop into a pair. Dont get more than 2, and only get one species, if you do otherwise you will most likely have issues. You could add more than one species of dwarf angel to a tank as long as there is room and as long as they are added at the same time. Having said that, I personally wouldnt try it in anything less than a 75, I've seen it done in tanks as small as a 40, bit I personally wouldnt put any dwarf angels in a 40 short of maybe a cherub angel, which are actually really cool fish. You mentioned either a flame angel or a lemonpeel angel...both are more aggressive species. I would not do either unless you had a 65 or bigger tank, and while I said dwarf angels can be mixed earlier, I have friends who insist that you should never attempt that with a lemonpeel, apparently they are really aggressive toward other dwarf angels, regardless of the tank. Most blennies are very cool fish, just be aware that if you ever get into tangs, bristletooth tangs (such as tomini or kole tangs) will get very aggressive with algae eating blennies because they target the same types of algae. Larger starry and lawnmower blennies may be able to hold their ground, but if you can plan ahead, I would avoid the stress to you and your fish. Finally, firefish are awesome fish, but they can get very shy around more aggressive species, to the point of hiding and even starving to death. They do really well in a very peaceful tank. Go with 1 firefish unless you know you have a mated pair, if you just guess and get 2 or more, there is a good chance you will end up with only 1 in the end, they pester each other to death, a lot like several species of damselfish. One last little point: you do not need an anemone to observe the hosting behavior clownfish are famous for. Clowns will do this in a variety of situations. Anemones can be difficult, for most people bubble tips are really the best option. They need good light and flow, and if you dont have a sump, I wouldnt even try it. My perculas are hosted in one of my frogspawns, and the male likes to hang out in my duncan, as well. These are much easier than anemones. Also, dont automatically expect the hosting behavior, it can take years to happen, even with anemones, and sometimes the clowns just never even develop an interest at all. Anemones also move around at times, and if you have corals, they can sting everything in their path, which can be annoying. Alright, my marathon post is done, I hope I gave you some interesting ideas and a better understanding on why people suggest what they suggest. Enjoy,
Scott
