Sounds to me like you added fish to a tank that wasn't finished cycling yet, or were suckered into trying to cycle your tank with just LR
, which is another of my pet peeves in this industry; aka 'bad advice list'. I guess the tried and try method of using damsels or a handfull of decaying shrimp is too easy anymore.
Your fish dealer should also be spanked for selling you some of these fish as well. Hippo tangs and angel fish have no place in a freshly cycled tank along with butterflys, and I'm not thrilled with the royal gramma either because of it's timidity and sensitivity to ick. Had this been a Bicolor Pseudochromis (dottyback), he woulnd't have taken any crap from the wrasse.
Ick is one of the most frustrating problems to deal with because novices often blame the wrong source. Ick is much like the common cold in humans; we all carry the virus at some point, but only come down with it when we are stressed or placed around new people in a contained environment. Marine fish are the same way, and considering your tank is fairly new, it's not helping much in terms of stress. The next contributor is fish shops that take in new fish on Tuesday, and sell them on Wednsday after the poor things have been bounced around in shipping containers half way around the world. Often times ick is not a problem at all in your tank, but fish were sick before you bought them.
The best advice I can give you about buying new marine fish is to scope out a specimen for a few weeks and make sure he's eating well at the aquarium shop and healthy, and *then* buy him. If your fish dealer is cool, he'll even let you put a deposit on them ahead of time while they acclimate. In this respect I disagree with my fellows here about a quarantine tank for new fish because I don't feel it's necessary. If it's a healthy fish at the aquarium shop, and your tank is running well, new fish should acclimate extremely quickly to your tank.
Assuming you just have fish in your tank, or fish plus hermit crabs and snails only, Ick outbreaks can be brought under control by dropping your salinity to .016-17 and raising the temp to 82-83F for a couple weeks. Easy enough to do really since all you have to do is drain some water and replace it with fresh. Note that I recommend doing this over a 2-day period to avoid stressing your bio system. Fish could normally care less about salinity and actually do better if it's lower vs higher. It's increasing salinity that stresses fish and going down that stresses soft invertebrates. There's an advantage to having a backbone.
I've also had good luck with malachite green in marine tanks dosed over a period of 5 days combined with the steps above, and find it less dangerous and residual than copper. Both *will* kill soft invertebrates though.
The plan above should take care of the ick problem, but the next step is where to go from here? My advice is to stop with fish purchases until you 'clean house' on the ick problem, and then be more selective on your purchases. I strongly recommend fish in the goby family for starters since they are among the hardiest and most compatible in new tanks, and less pugnacious than damsels. Firefish gobies are docile, peacefull (at least to other fish) and typically very hardy along with Watchman gobies. Blennies are also super tough and typically docile marine fish, especially the scooter, and I'm seeing more and more canary blennies which are not only very pretty, but very rugged and peacefull. I pulled a half chewed up canary blenny out of a power head a few weeks ago, and 5 minutes after extracting him from the impellar he was begging for food even though half his body was in shreds. He's now back to full health. Wrasses are also pretty tough fish, but if your current one has established dominance due to lack of competition, he might be a problem. I'm not familiar with your type though. Yellow wrasses are pretty mild with the common 6 line being more aggresive.
Clownfish are usually in the 'more hardy' category, so your bad experience had to have been caused by a really bad water condition, or simply a sick fish. I'd wait a month or two and try another, perhaps a tomato or maroon since I've found them tougher than percs, although more territorial towards other clowns.
Essentially I want you to do is stop with the fancy 'high maintence' fish and get a good backbone of more hardy utility fish going first. I also strongly recommend getting some hermit crabs and turbo snails if you don't already, if anything because they kick out a lot of ammonia and keep a new tank cycled better. You can get some of that dried sea-weed stuff used for tangs, attach it to a plastic feeder clip and throw it in a tank full of hermit crabs and they'll come a runnin' which kids find kind of cool. Sally light foot crabs are also very tough and exellent for new tanks. Cleaner shrimp are worth a look, but they tend to be sensitive to PH
changes and should only be added once the tank has stablized and free of ick treatments. After 3-4 months, you can start getting fancy and look at a dwarf angel as on option or perhaps a yellow tang, but in the meantime I'd stick to the fish above so can you stop blowing cash.